Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

52 files changed, 12687 insertions, 0 deletions

diff --git a/gfx/src/AAStroke.h b/gfx/src/AAStroke.h
new file mode 100644
index 0000000000..685cf60647
--- /dev/null
+++ b/gfx/src/AAStroke.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_GFX_AA_STROKE_H
+#define MOZILLA_GFX_AA_STROKE_H
+
+#include <stddef.h>
+
+namespace AAStroke {
+
+enum class LineCap { Round, Square, Butt };
+enum class LineJoin { Round, Miter, Bevel };
+struct StrokeStyle {
+  float width;
+  LineCap cap;
+  LineJoin join;
+  float miter_limit;
+};
+struct Stroker;
+struct OutputVertex {
+  float x;
+  float y;
+  float coverage;
+};
+struct VertexBuffer {
+  OutputVertex* data;
+  size_t len;
+};
+
+extern "C" {
+Stroker* aa_stroke_new(const StrokeStyle* style,
+                       OutputVertex* output_ptr = nullptr,
+                       size_t output_capacity = 0);
+void aa_stroke_move_to(Stroker* s, float x, float y, bool closed);
+void aa_stroke_line_to(Stroker* s, float x, float y, bool end);
+void aa_stroke_curve_to(Stroker* s, float c1x, float c1y, float c2x, float c2y,
+                        float x, float y, bool end);
+void aa_stroke_close(Stroker* s);
+VertexBuffer aa_stroke_finish(Stroker* s);
+void aa_stroke_vertex_buffer_release(VertexBuffer vb);
+void aa_stroke_release(Stroker* s);
+};
+
+}  // namespace AAStroke
+
+#endif  // MOZILLA_GFX_AA_STROKE_H
diff --git a/gfx/src/AppUnits.h b/gfx/src/AppUnits.h
new file mode 100644
index 0000000000..2b00ec7d56
--- /dev/null
+++ b/gfx/src/AppUnits.h
@@ -0,0 +1,18 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_AppUnits_h
+#define mozilla_AppUnits_h
+
+#include <stdint.h>
+
+namespace mozilla {
+constexpr inline int32_t AppUnitsPerCSSPixel() { return 60; }
+constexpr inline int32_t AppUnitsPerCSSInch() {
+  return 96 * AppUnitsPerCSSPixel();
+}
+}  // namespace mozilla
+#endif /* _NS_APPUNITS_H_ */
diff --git a/gfx/src/ArrayView.h b/gfx/src/ArrayView.h
new file mode 100644
index 0000000000..e5d5ace976
--- /dev/null
+++ b/gfx/src/ArrayView.h
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_GFX_ARRAY_VIEW_H_
+#define MOZILLA_GFX_ARRAY_VIEW_H_
+
+#include "nsTArray.h"
+
+/* This is similar to mfbt/Range.h but has implicit conversion
+ * from nsTArray and less bounds checking.
+ * For now, prefer Range over ArrayView */
+
+namespace mozilla {
+namespace gfx {
+
+template <typename T>
+class ArrayView {
+ public:
+  MOZ_IMPLICIT ArrayView(const nsTArray<T>& aData)
+      : mData(aData.Elements()), mLength(aData.Length()) {}
+  ArrayView(const T* aData, const size_t aLength)
+      : mData(aData), mLength(aLength) {}
+  const T& operator[](const size_t aIdx) const { return mData[aIdx]; }
+  size_t Length() const { return mLength; }
+  const T* Data() const { return mData; }
+
+ private:
+  const T* mData;
+  const size_t mLength;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif /* MOZILLA_GFX_ARRAY_VIEW_H_ */
diff --git a/gfx/src/CompositorHitTestInfo.h b/gfx/src/CompositorHitTestInfo.h
new file mode 100644
index 0000000000..840d1e5dd5
--- /dev/null
+++ b/gfx/src/CompositorHitTestInfo.h
@@ -0,0 +1,113 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_GFX_COMPOSITORHITTESTINFO_H_
+#define MOZILLA_GFX_COMPOSITORHITTESTINFO_H_
+
+#include "mozilla/EnumSet.h"
+#include "mozilla/EnumTypeTraits.h"
+
+namespace mozilla {
+namespace gfx {
+
+// This set of flags is used to figure out what information a frame has
+// that is relevant to hit-testing in the compositor. The flags are
+// intentionally set up so that if all of them are 0 the item is effectively
+// invisible to hit-testing, and no information for this frame needs to be
+// sent to the compositor.
+// Each enumerator is annotated with the value it contributes to an
+// EnumSet (2 ^ <value of enumerator>), in hexadecimal.
+enum class CompositorHitTestFlags : uint8_t {
+  // The frame participates in hit-testing
+  eVisibleToHitTest = 0,  // 0x0001
+
+  // The frame may have odd shapes that requires the main thread to do accurate
+  // hit-testing.
+  eIrregularArea,  // 0x0002
+  // The frame has APZ-aware listeners and so inputs targeted at this area
+  // need to be handled by the main thread before APZ can use them, as they
+  // might be prevent-defaulted.
+  eApzAwareListeners,  // 0x0004
+  // This is an inactive scrollframe or unlayerized scrollthumb. In this state
+  // it cannot be used by APZ for async scrolling, so APZ will defer to the main
+  // thread.
+  eInactiveScrollframe,  // 0x0008
+
+  // The touch action flags are set up so that the default of
+  // touch-action:auto on an element leaves all the flags as 0.
+  eTouchActionPanXDisabled,           // 0x0010
+  eTouchActionPanYDisabled,           // 0x0020
+  eTouchActionPinchZoomDisabled,      // 0x0040
+  eTouchActionAnimatingZoomDisabled,  // 0x0080
+
+  // The frame is a scrollbar or a subframe inside a scrollbar (including
+  // scroll thumbs)
+  eScrollbar,  // 0x0100
+  // The frame is a scrollthumb. If this is set then eScrollbar will also be
+  // set, unless gecko somehow generates a scroll thumb without a containing
+  // scrollbar.
+  eScrollbarThumb,  // 0x0200
+  // If eScrollbar is set, this flag indicates if the scrollbar is a vertical
+  // one (if set) or a horizontal one (if not set)
+  eScrollbarVertical,  // 0x0400
+
+  // Events targeting this frame should only be processed if a target
+  // confirmation is received from the main thread. If no such confirmation
+  // is received within a timeout period, the event may be dropped.
+  // Only meaningful in combination with eDispatchToContent.
+  eRequiresTargetConfirmation,  // 0x0800
+
+  // Bits 0x1000, 0x2000, 0x4000, and 0x8000 are used by SideBitsPacked in
+  // WebRenderAPI.cpp when we pack SideBits and CompositorHitTestInfo into a
+  // uint16_t and pass in into webrender to store in the item tag.
+
+};
+
+using CompositorHitTestInfo = EnumSet<CompositorHitTestFlags, uint32_t>;
+
+// A CompositorHitTestInfo with none of the flags set
+constexpr CompositorHitTestInfo CompositorHitTestInvisibleToHit;
+
+// Mask to check for all the touch-action flags at once
+constexpr CompositorHitTestInfo CompositorHitTestTouchActionMask(
+    CompositorHitTestFlags::eTouchActionPanXDisabled,
+    CompositorHitTestFlags::eTouchActionPanYDisabled,
+    CompositorHitTestFlags::eTouchActionPinchZoomDisabled,
+    CompositorHitTestFlags::eTouchActionAnimatingZoomDisabled);
+
+// Mask to check all the flags that involve APZ waiting for results from the
+// main thread
+constexpr CompositorHitTestInfo CompositorHitTestDispatchToContent(
+    CompositorHitTestFlags::eIrregularArea,
+    CompositorHitTestFlags::eApzAwareListeners,
+    CompositorHitTestFlags::eInactiveScrollframe);
+
+}  // namespace gfx
+
+// Used for IPDL serialization. The 'value' have to be the biggest enum from
+// CompositorHitTestFlags.
+template <>
+struct MaxEnumValue<::mozilla::gfx::CompositorHitTestFlags> {
+  static constexpr unsigned int value = static_cast<unsigned int>(
+      gfx::CompositorHitTestFlags::eRequiresTargetConfirmation);
+};
+
+namespace gfx {
+
+// Checks if the CompositorHitTestFlags max enum value is less than N.
+template <int N>
+static constexpr bool DoesCompositorHitTestInfoFitIntoBits() {
+  if (MaxEnumValue<CompositorHitTestInfo::valueType>::value < N) {
+    return true;
+  }
+
+  return false;
+}
+}  // namespace gfx
+
+}  // namespace mozilla
+
+#endif /* MOZILLA_GFX_COMPOSITORHITTESTINFO_H_ */
diff --git a/gfx/src/DriverCrashGuard.cpp b/gfx/src/DriverCrashGuard.cpp
new file mode 100644
index 0000000000..9b68c07e55
--- /dev/null
+++ b/gfx/src/DriverCrashGuard.cpp
@@ -0,0 +1,528 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "DriverCrashGuard.h"
+#include "gfxEnv.h"
+#include "gfxConfig.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsExceptionHandler.h"
+#include "nsServiceManagerUtils.h"
+#include "nsString.h"
+#include "nsXULAppAPI.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_webgl.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/Components.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/dom/ContentChild.h"
+
+namespace mozilla {
+namespace gfx {
+
+static const size_t NUM_CRASH_GUARD_TYPES = size_t(CrashGuardType::NUM_TYPES);
+static const char* sCrashGuardNames[] = {
+    "d3d11layers",
+    "glcontext",
+    "wmfvpxvideo",
+};
+static_assert(MOZ_ARRAY_LENGTH(sCrashGuardNames) == NUM_CRASH_GUARD_TYPES,
+              "CrashGuardType updated without a name string");
+
+static inline void BuildCrashGuardPrefName(CrashGuardType aType,
+                                           nsCString& aOutPrefName) {
+  MOZ_ASSERT(aType < CrashGuardType::NUM_TYPES);
+  MOZ_ASSERT(sCrashGuardNames[size_t(aType)]);
+
+  aOutPrefName.AssignLiteral("gfx.crash-guard.status.");
+  aOutPrefName.Append(sCrashGuardNames[size_t(aType)]);
+}
+
+DriverCrashGuard::DriverCrashGuard(CrashGuardType aType,
+                                   dom::ContentParent* aContentParent)
+    : mType(aType),
+      mMode(aContentParent ? Mode::Proxy : Mode::Normal),
+      mInitialized(false),
+      mGuardActivated(false),
+      mCrashDetected(false) {
+  BuildCrashGuardPrefName(aType, mStatusPref);
+}
+
+void DriverCrashGuard::InitializeIfNeeded() {
+  if (mInitialized) {
+    return;
+  }
+
+  mInitialized = true;
+  Initialize();
+}
+
+static inline bool AreCrashGuardsEnabled(CrashGuardType aType) {
+  // Crash guard isn't supported in the GPU or RDD process since the entire
+  // process is basically a crash guard.
+  if (XRE_IsGPUProcess() || XRE_IsRDDProcess()) {
+    return false;
+  }
+#ifdef NIGHTLY_BUILD
+  // We only use the crash guard on non-nightly channels, since the nightly
+  // channel is for development and having graphics features perma-disabled
+  // is rather annoying.  Unless the user forces is with an environment
+  // variable, which comes in handy for testing.
+  // We handle the WMFVPXVideo crash guard differently to the other and always
+  // enable it as it completely breaks playback and there's no way around it.
+  if (aType != CrashGuardType::WMFVPXVideo) {
+    return gfxEnv::MOZ_FORCE_CRASH_GUARD_NIGHTLY();
+  }
+#endif
+  // Check to see if all guards have been disabled through the environment.
+  return !gfxEnv::MOZ_DISABLE_CRASH_GUARD();
+}
+
+void DriverCrashGuard::Initialize() {
+  if (!AreCrashGuardsEnabled(mType)) {
+    return;
+  }
+
+  // Using DriverCrashGuard off the main thread currently does not work. Under
+  // e10s it could conceivably work by dispatching the IPC calls via the main
+  // thread. In the parent process this would be harder. For now, we simply
+  // exit early instead.
+  if (!NS_IsMainThread()) {
+    return;
+  }
+
+  mGfxInfo = components::GfxInfo::Service();
+
+  if (XRE_IsContentProcess()) {
+    // Ask the parent whether or not activating the guard is okay. The parent
+    // won't bother if it detected a crash.
+    dom::ContentChild* cc = dom::ContentChild::GetSingleton();
+    cc->SendBeginDriverCrashGuard(uint32_t(mType), &mCrashDetected);
+    if (mCrashDetected) {
+      LogFeatureDisabled();
+      return;
+    }
+
+    ActivateGuard();
+    return;
+  }
+
+  // Always check whether or not the lock file exists. For example, we could
+  // have crashed creating a D3D9 device in the parent process, and on restart
+  // are now requesting one in the child process. We catch everything here.
+  if (RecoverFromCrash()) {
+    mCrashDetected = true;
+    return;
+  }
+
+  // If the environment has changed, we always activate the guard. In the
+  // parent process this performs main-thread disk I/O. Child process guards
+  // only incur an IPC cost, so if we're proxying for a child process, we
+  // play it safe and activate the guard as long as we don't expect it to
+  // crash.
+  if (CheckOrRefreshEnvironment() ||
+      (mMode == Mode::Proxy && GetStatus() != DriverInitStatus::Crashed)) {
+    ActivateGuard();
+    return;
+  }
+
+  // If we got here and our status is "crashed", then the environment has not
+  // updated and we do not want to attempt to use the driver again.
+  if (GetStatus() == DriverInitStatus::Crashed) {
+    mCrashDetected = true;
+    LogFeatureDisabled();
+  }
+}
+
+DriverCrashGuard::~DriverCrashGuard() {
+  if (!mGuardActivated) {
+    return;
+  }
+
+  if (XRE_IsParentProcess()) {
+    if (mGuardFile) {
+      mGuardFile->Remove(false);
+    }
+
+    // If during our initialization, no other process encountered a crash, we
+    // proceed to mark the status as okay.
+    if (GetStatus() != DriverInitStatus::Crashed) {
+      SetStatus(DriverInitStatus::Okay);
+    }
+  } else {
+    dom::ContentChild::GetSingleton()->SendEndDriverCrashGuard(uint32_t(mType));
+  }
+
+  CrashReporter::RemoveCrashReportAnnotation(
+      CrashReporter::Annotation::GraphicsStartupTest);
+}
+
+bool DriverCrashGuard::Crashed() {
+  InitializeIfNeeded();
+
+  // Note, we read mCrashDetected instead of GetStatus(), since in child
+  // processes we're not guaranteed that the prefs have been synced in
+  // time.
+  return mCrashDetected;
+}
+
+nsCOMPtr<nsIFile> DriverCrashGuard::GetGuardFile() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  nsCString filename;
+  filename.Assign(sCrashGuardNames[size_t(mType)]);
+  filename.AppendLiteral(".guard");
+
+  nsCOMPtr<nsIFile> file;
+  NS_GetSpecialDirectory(NS_APP_USER_PROFILE_LOCAL_50_DIR,
+                         getter_AddRefs(file));
+  if (!file) {
+    return nullptr;
+  }
+  if (!NS_SUCCEEDED(file->AppendNative(filename))) {
+    return nullptr;
+  }
+  return file;
+}
+
+void DriverCrashGuard::ActivateGuard() {
+  mGuardActivated = true;
+
+  // Anotate crash reports only if we're a real guard. Otherwise, we could
+  // attribute a random parent process crash to a graphics problem in a child
+  // process.
+  if (mMode != Mode::Proxy) {
+    CrashReporter::AnnotateCrashReport(
+        CrashReporter::Annotation::GraphicsStartupTest, true);
+  }
+
+  // If we're in the content process, the rest of the guarding is handled
+  // in the parent.
+  if (XRE_IsContentProcess()) {
+    return;
+  }
+
+  SetStatus(DriverInitStatus::Attempting);
+
+  if (mMode != Mode::Proxy) {
+    // In parent process guards, we use two tombstones to detect crashes: a
+    // preferences and a zero-byte file on the filesystem.
+    FlushPreferences();
+
+    // Create a temporary tombstone/lockfile.
+    FILE* fp = nullptr;
+    mGuardFile = GetGuardFile();
+    if (!mGuardFile || !NS_SUCCEEDED(mGuardFile->OpenANSIFileDesc("w", &fp))) {
+      return;
+    }
+    fclose(fp);
+  }
+}
+
+void DriverCrashGuard::NotifyCrashed() {
+  SetStatus(DriverInitStatus::Crashed);
+  FlushPreferences();
+  LogCrashRecovery();
+}
+
+bool DriverCrashGuard::RecoverFromCrash() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  nsCOMPtr<nsIFile> file = GetGuardFile();
+  bool exists;
+  if ((file && NS_SUCCEEDED(file->Exists(&exists)) && exists) ||
+      (GetStatus() == DriverInitStatus::Attempting)) {
+    // If we get here, we've just recovered from a crash. Disable acceleration
+    // until the environment changes.
+    if (file) {
+      file->Remove(false);
+    }
+    NotifyCrashed();
+    return true;
+  }
+  return false;
+}
+
+// Return true if the caller should proceed to guard for crashes. False if
+// the environment has not changed. We persist the "changed" status across
+// calls, so that after an environment changes, all guards for the new
+// session are activated rather than just the first.
+bool DriverCrashGuard::CheckOrRefreshEnvironment() {
+  // Our result can be cached statically since we don't check live prefs.
+  // We need to cache once per crash guard type.
+  // The first call to CheckOrRefrechEnvironment will always return true should
+  // the configuration had changed, following calls will return false.
+  static bool sBaseInfoChanged[NUM_CRASH_GUARD_TYPES];
+  static bool sBaseInfoChecked[NUM_CRASH_GUARD_TYPES];
+
+  const uint32_t type = uint32_t(mType);
+  if (!sBaseInfoChecked[type]) {
+    // None of the prefs we care about, so we cache the result statically.
+    sBaseInfoChecked[type] = true;
+    sBaseInfoChanged[type] = UpdateBaseEnvironment();
+  }
+
+  // Always update the full environment, even if the base info didn't change.
+  bool result = UpdateEnvironment() || sBaseInfoChanged[type] ||
+                GetStatus() == DriverInitStatus::Unknown;
+  sBaseInfoChanged[type] = false;
+  return result;
+}
+
+bool DriverCrashGuard::UpdateBaseEnvironment() {
+  bool changed = false;
+  if (mGfxInfo) {
+    nsString value;
+
+    // Driver properties.
+    mGfxInfo->GetAdapterDriverVersion(value);
+    changed |= CheckAndUpdatePref("driverVersion", value);
+    mGfxInfo->GetAdapterDeviceID(value);
+    changed |= CheckAndUpdatePref("deviceID", value);
+  }
+
+  // Firefox properties.
+  changed |= CheckAndUpdatePref(
+      "appVersion", NS_LITERAL_STRING_FROM_CSTRING(MOZ_APP_VERSION));
+
+  return changed;
+}
+
+bool DriverCrashGuard::FeatureEnabled(int aFeature, bool aDefault) {
+  if (!mGfxInfo) {
+    return aDefault;
+  }
+  int32_t status;
+  nsCString discardFailureId;
+  if (!NS_SUCCEEDED(
+          mGfxInfo->GetFeatureStatus(aFeature, discardFailureId, &status))) {
+    return false;
+  }
+  return status == nsIGfxInfo::FEATURE_STATUS_OK;
+}
+
+bool DriverCrashGuard::CheckAndUpdateBoolPref(const char* aPrefName,
+                                              bool aCurrentValue) {
+  std::string pref = GetFullPrefName(aPrefName);
+
+  bool oldValue;
+  if (NS_SUCCEEDED(Preferences::GetBool(pref.c_str(), &oldValue)) &&
+      oldValue == aCurrentValue) {
+    return false;
+  }
+  Preferences::SetBool(pref.c_str(), aCurrentValue);
+  return true;
+}
+
+bool DriverCrashGuard::CheckAndUpdatePref(const char* aPrefName,
+                                          const nsAString& aCurrentValue) {
+  std::string pref = GetFullPrefName(aPrefName);
+
+  nsAutoString oldValue;
+  Preferences::GetString(pref.c_str(), oldValue);
+  if (oldValue == aCurrentValue) {
+    return false;
+  }
+  Preferences::SetString(pref.c_str(), aCurrentValue);
+  return true;
+}
+
+std::string DriverCrashGuard::GetFullPrefName(const char* aPref) {
+  return std::string("gfx.crash-guard.") +
+         std::string(sCrashGuardNames[uint32_t(mType)]) + std::string(".") +
+         std::string(aPref);
+}
+
+DriverInitStatus DriverCrashGuard::GetStatus() const {
+  return (DriverInitStatus)Preferences::GetInt(mStatusPref.get(), 0);
+}
+
+void DriverCrashGuard::SetStatus(DriverInitStatus aStatus) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  Preferences::SetInt(mStatusPref.get(), int32_t(aStatus));
+}
+
+void DriverCrashGuard::FlushPreferences() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  if (nsIPrefService* prefService = Preferences::GetService()) {
+    static_cast<Preferences*>(prefService)->SavePrefFileBlocking();
+  }
+}
+
+void DriverCrashGuard::ForEachActiveCrashGuard(
+    const CrashGuardCallback& aCallback) {
+  for (size_t i = 0; i < NUM_CRASH_GUARD_TYPES; i++) {
+    CrashGuardType type = static_cast<CrashGuardType>(i);
+
+    if (!AreCrashGuardsEnabled(type)) {
+      // Even if guards look active (via prefs), they can be ignored if globally
+      // disabled.
+      continue;
+    }
+
+    nsCString prefName;
+    BuildCrashGuardPrefName(type, prefName);
+
+    auto status =
+        static_cast<DriverInitStatus>(Preferences::GetInt(prefName.get(), 0));
+    if (status != DriverInitStatus::Crashed) {
+      continue;
+    }
+
+    aCallback(sCrashGuardNames[i], prefName.get());
+  }
+}
+
+D3D11LayersCrashGuard::D3D11LayersCrashGuard(dom::ContentParent* aContentParent)
+    : DriverCrashGuard(CrashGuardType::D3D11Layers, aContentParent) {}
+
+void D3D11LayersCrashGuard::Initialize() {
+  if (!XRE_IsParentProcess()) {
+    // We assume the parent process already performed crash detection for
+    // graphics devices.
+    return;
+  }
+
+  DriverCrashGuard::Initialize();
+
+  // If no telemetry states have been recorded, this will set the state to okay.
+  // Otherwise, it will have no effect.
+  RecordTelemetry(TelemetryState::Okay);
+}
+
+bool D3D11LayersCrashGuard::UpdateEnvironment() {
+  // Our result can be cached statically since we don't check live prefs.
+  static bool checked = false;
+
+  if (checked) {
+    // We no longer need to bypass the crash guard.
+    return false;
+  }
+
+  checked = true;
+
+  bool changed = false;
+  // Feature status.
+#if defined(XP_WIN)
+  bool d2dEnabled = StaticPrefs::gfx_direct2d_force_enabled_AtStartup() ||
+                    (!StaticPrefs::gfx_direct2d_disabled_AtStartup() &&
+                     FeatureEnabled(nsIGfxInfo::FEATURE_DIRECT2D));
+  changed |= CheckAndUpdateBoolPref("feature-d2d", d2dEnabled);
+
+  bool d3d11Enabled = gfxConfig::IsEnabled(Feature::D3D11_COMPOSITING);
+  changed |= CheckAndUpdateBoolPref("feature-d3d11", d3d11Enabled);
+  if (changed) {
+    RecordTelemetry(TelemetryState::EnvironmentChanged);
+  }
+#endif
+
+  return changed;
+}
+
+void D3D11LayersCrashGuard::LogCrashRecovery() {
+  RecordTelemetry(TelemetryState::RecoveredFromCrash);
+  gfxCriticalNote << "D3D11 layers just crashed; D3D11 will be disabled.";
+}
+
+void D3D11LayersCrashGuard::LogFeatureDisabled() {
+  RecordTelemetry(TelemetryState::FeatureDisabled);
+  gfxCriticalNote << "D3D11 layers disabled due to a prior crash.";
+}
+
+void D3D11LayersCrashGuard::RecordTelemetry(TelemetryState aState) {
+  // D3D11LayersCrashGuard is a no-op in the child process.
+  if (!XRE_IsParentProcess()) {
+    return;
+  }
+
+  // Since we instantiate this class more than once, make sure we only record
+  // the first state (since that is really all we care about).
+  static bool sTelemetryStateRecorded = false;
+  if (sTelemetryStateRecorded) {
+    return;
+  }
+
+  Telemetry::Accumulate(Telemetry::GRAPHICS_DRIVER_STARTUP_TEST,
+                        int32_t(aState));
+  sTelemetryStateRecorded = true;
+}
+
+GLContextCrashGuard::GLContextCrashGuard(dom::ContentParent* aContentParent)
+    : DriverCrashGuard(CrashGuardType::GLContext, aContentParent) {}
+
+void GLContextCrashGuard::Initialize() {
+  if (XRE_IsContentProcess()) {
+    // Disable the GL crash guard in content processes, since we're not going
+    // to lose the entire browser and we don't want to hinder WebGL
+    // availability.
+    return;
+  }
+
+#if defined(MOZ_WIDGET_ANDROID)
+  // Disable the WebGL crash guard on Android - it doesn't use E10S, and
+  // its drivers will essentially never change, so the crash guard could
+  // permanently disable WebGL.
+  return;
+#endif
+
+  DriverCrashGuard::Initialize();
+}
+
+bool GLContextCrashGuard::UpdateEnvironment() {
+  static bool checked = false;
+
+  if (checked) {
+    // We no longer need to bypass the crash guard.
+    return false;
+  }
+
+  checked = true;
+
+  bool changed = false;
+
+#if defined(XP_WIN)
+  changed |= CheckAndUpdateBoolPref("gfx.driver-init.webgl-angle-force-d3d11",
+                                    StaticPrefs::webgl_angle_force_d3d11());
+  changed |= CheckAndUpdateBoolPref("gfx.driver-init.webgl-angle-try-d3d11",
+                                    StaticPrefs::webgl_angle_try_d3d11());
+  changed |= CheckAndUpdateBoolPref("gfx.driver-init.webgl-angle-force-warp",
+                                    StaticPrefs::webgl_angle_force_warp());
+  changed |= CheckAndUpdateBoolPref(
+      "gfx.driver-init.webgl-angle",
+      FeatureEnabled(nsIGfxInfo::FEATURE_WEBGL_ANGLE, false));
+  changed |= CheckAndUpdateBoolPref(
+      "gfx.driver-init.direct3d11-angle",
+      FeatureEnabled(nsIGfxInfo::FEATURE_DIRECT3D_11_ANGLE, false));
+#endif
+
+  return changed;
+}
+
+void GLContextCrashGuard::LogCrashRecovery() {
+  gfxCriticalNote << "GLContext just crashed.";
+}
+
+void GLContextCrashGuard::LogFeatureDisabled() {
+  gfxCriticalNote << "GLContext remains enabled despite a previous crash.";
+}
+
+WMFVPXVideoCrashGuard::WMFVPXVideoCrashGuard(dom::ContentParent* aContentParent)
+    : DriverCrashGuard(CrashGuardType::WMFVPXVideo, aContentParent) {}
+
+void WMFVPXVideoCrashGuard::LogCrashRecovery() {
+  gfxCriticalNote
+      << "WMF VPX decoder just crashed; hardware video will be disabled.";
+}
+
+void WMFVPXVideoCrashGuard::LogFeatureDisabled() {
+  gfxCriticalNote
+      << "WMF VPX video decoding is disabled due to a previous crash.";
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/src/DriverCrashGuard.h b/gfx/src/DriverCrashGuard.h
new file mode 100644
index 0000000000..1cb8d78d56
--- /dev/null
+++ b/gfx/src/DriverCrashGuard.h
@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef gfx_src_DriverCrashGuard_h__
+#define gfx_src_DriverCrashGuard_h__
+
+#include "nsCOMPtr.h"
+#include "nsIGfxInfo.h"
+#include "nsIFile.h"
+#include "nsString.h"
+#include <functional>
+#include <string>
+
+namespace mozilla {
+
+namespace dom {
+class ContentParent;
+}  // namespace dom
+
+namespace gfx {
+
+enum class DriverInitStatus {
+  // Drivers have not been initialized yet.
+  Unknown,
+
+  // We're attempting to initialize drivers.
+  Attempting,
+
+  // Drivers were successfully initialized last run.
+  Okay,
+
+  // We crashed during driver initialization, and have restarted.
+  Crashed
+};
+
+enum class CrashGuardType : uint32_t {
+  D3D11Layers,
+  GLContext,
+  WMFVPXVideo,
+  // Add new entries above this line, update the name array in
+  // DriverCrashGuard.cpp, make sure to add an entry in ContentParent.cpp,
+  // and add a fluent identifier in aboutSupport.ftl.
+
+  NUM_TYPES
+};
+
+// DriverCrashGuard is used to detect crashes at graphics driver callsites.
+//
+// If the graphics environment is unrecognized or has changed since the last
+// session, the crash guard will activate and will detect any crashes within
+// the scope of the guard object.
+//
+// If a callsite has a previously encountered crash, and the environment has
+// not changed since the last session, then the guard will set a status flag
+// indicating that the driver should not be used.
+class DriverCrashGuard {
+ public:
+  DriverCrashGuard(CrashGuardType aType, dom::ContentParent* aContentParent);
+  virtual ~DriverCrashGuard();
+
+  bool Crashed();
+  void NotifyCrashed();
+
+  // These are the values reported to Telemetry (GRAPHICS_DRIVER_STARTUP_TEST).
+  // Values should not change; add new values to the end.
+  enum class TelemetryState {
+    Okay = 0,
+    EnvironmentChanged = 1,
+    RecoveredFromCrash = 2,
+    FeatureDisabled = 3
+  };
+
+  enum class Mode {
+    // Normal operation.
+    Normal,
+
+    // Acting as a proxy between the parent and child process.
+    Proxy
+  };
+
+  typedef std::function<void(const char* aName, const char* aPrefName)>
+      CrashGuardCallback;
+  static void ForEachActiveCrashGuard(const CrashGuardCallback& aCallback);
+
+ protected:
+  virtual void Initialize();
+  // UpdateEnvironment needs to return true should we need to attempt the
+  // operation once again.
+  // It should return true once only so that in case of a crash, we won't
+  // needlessly attempt the operation over and over again leading to continual
+  // crashes. several times
+  virtual bool UpdateEnvironment() {
+    // We don't care about any extra preferences here.
+    return false;
+  }
+  virtual void LogCrashRecovery() = 0;
+  virtual void LogFeatureDisabled() = 0;
+
+  // Helper functions.
+  bool FeatureEnabled(int aFeature, bool aDefault = true);
+  bool CheckAndUpdatePref(const char* aPrefName,
+                          const nsAString& aCurrentValue);
+  bool CheckAndUpdateBoolPref(const char* aPrefName, bool aCurrentValue);
+  std::string GetFullPrefName(const char* aPref);
+
+ private:
+  // Either process.
+  void InitializeIfNeeded();
+  bool CheckOrRefreshEnvironment();
+  bool UpdateBaseEnvironment();
+  DriverInitStatus GetStatus() const;
+
+  // Parent process only.
+  nsCOMPtr<nsIFile> GetGuardFile();
+  bool RecoverFromCrash();
+  void ActivateGuard();
+  void FlushPreferences();
+  void SetStatus(DriverInitStatus aStatus);
+
+ private:
+  CrashGuardType mType;
+  Mode mMode;
+  bool mInitialized;
+  bool mGuardActivated;
+  bool mCrashDetected;
+  nsCOMPtr<nsIFile> mGuardFile;
+
+ protected:
+  nsCString mStatusPref;
+  nsCOMPtr<nsIGfxInfo> mGfxInfo;
+};
+
+class D3D11LayersCrashGuard final : public DriverCrashGuard {
+ public:
+  explicit D3D11LayersCrashGuard(dom::ContentParent* aContentParent = nullptr);
+
+ protected:
+  void Initialize() override;
+  bool UpdateEnvironment() override;
+  void LogCrashRecovery() override;
+  void LogFeatureDisabled() override;
+
+ private:
+  void RecordTelemetry(TelemetryState aState);
+};
+
+class GLContextCrashGuard final : public DriverCrashGuard {
+ public:
+  explicit GLContextCrashGuard(dom::ContentParent* aContentParent = nullptr);
+  void Initialize() override;
+
+ protected:
+  bool UpdateEnvironment() override;
+  void LogCrashRecovery() override;
+  void LogFeatureDisabled() override;
+};
+
+class WMFVPXVideoCrashGuard final : public DriverCrashGuard {
+ public:
+  explicit WMFVPXVideoCrashGuard(dom::ContentParent* aContentParent = nullptr);
+
+ protected:
+  void LogCrashRecovery() override;
+  void LogFeatureDisabled() override;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // gfx_src_DriverCrashGuard_h__
diff --git a/gfx/src/FilterDescription.h b/gfx/src/FilterDescription.h
new file mode 100644
index 0000000000..8c2ae12c98
--- /dev/null
+++ b/gfx/src/FilterDescription.h
@@ -0,0 +1,142 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __FilterDescription_h
+#define __FilterDescription_h
+
+#include "FilterSupport.h"
+#include "mozilla/Variant.h"
+#include "mozilla/gfx/Rect.h"
+#include "nsTArray.h"
+
+namespace mozilla::gfx {
+class FilterPrimitiveDescription;
+}
+
+MOZ_DECLARE_RELOCATE_USING_MOVE_CONSTRUCTOR(
+    mozilla::gfx::FilterPrimitiveDescription)
+
+namespace mozilla::gfx {
+typedef Variant<
+    EmptyAttributes, BlendAttributes, MorphologyAttributes,
+    ColorMatrixAttributes, FloodAttributes, TileAttributes,
+    ComponentTransferAttributes, OpacityAttributes, ConvolveMatrixAttributes,
+    OffsetAttributes, DisplacementMapAttributes, TurbulenceAttributes,
+    CompositeAttributes, MergeAttributes, ImageAttributes,
+    GaussianBlurAttributes, DropShadowAttributes, DiffuseLightingAttributes,
+    SpecularLightingAttributes, ToAlphaAttributes>
+    PrimitiveAttributes;
+
+/**
+ * A data structure to carry attributes for a given primitive that's part of a
+ * filter. Will be serializable via IPDL, so it must not contain complex
+ * functionality.
+ * Used as part of a FilterDescription.
+ */
+class FilterPrimitiveDescription final {
+ public:
+  enum {
+    kPrimitiveIndexSourceGraphic = -1,
+    kPrimitiveIndexSourceAlpha = -2,
+    kPrimitiveIndexFillPaint = -3,
+    kPrimitiveIndexStrokePaint = -4
+  };
+
+  FilterPrimitiveDescription();
+  explicit FilterPrimitiveDescription(PrimitiveAttributes&& aAttributes);
+  FilterPrimitiveDescription(FilterPrimitiveDescription&& aOther) = default;
+  FilterPrimitiveDescription& operator=(FilterPrimitiveDescription&& aOther) =
+      default;
+  FilterPrimitiveDescription(const FilterPrimitiveDescription& aOther)
+      : mAttributes(aOther.mAttributes),
+        mInputPrimitives(aOther.mInputPrimitives.Clone()),
+        mFilterPrimitiveSubregion(aOther.mFilterPrimitiveSubregion),
+        mFilterSpaceBounds(aOther.mFilterSpaceBounds),
+        mInputColorSpaces(aOther.mInputColorSpaces.Clone()),
+        mOutputColorSpace(aOther.mOutputColorSpace),
+        mIsTainted(aOther.mIsTainted) {}
+
+  const PrimitiveAttributes& Attributes() const { return mAttributes; }
+  PrimitiveAttributes& Attributes() { return mAttributes; }
+
+  IntRect PrimitiveSubregion() const { return mFilterPrimitiveSubregion; }
+  IntRect FilterSpaceBounds() const { return mFilterSpaceBounds; }
+  bool IsTainted() const { return mIsTainted; }
+
+  size_t NumberOfInputs() const { return mInputPrimitives.Length(); }
+  int32_t InputPrimitiveIndex(size_t aInputIndex) const {
+    return aInputIndex < mInputPrimitives.Length()
+               ? mInputPrimitives[aInputIndex]
+               : 0;
+  }
+
+  ColorSpace InputColorSpace(size_t aInputIndex) const {
+    return aInputIndex < mInputColorSpaces.Length()
+               ? mInputColorSpaces[aInputIndex]
+               : ColorSpace();
+  }
+
+  ColorSpace OutputColorSpace() const { return mOutputColorSpace; }
+
+  void SetPrimitiveSubregion(const IntRect& aRect) {
+    mFilterPrimitiveSubregion = aRect;
+  }
+
+  void SetFilterSpaceBounds(const IntRect& aRect) {
+    mFilterSpaceBounds = aRect;
+  }
+
+  void SetIsTainted(bool aIsTainted) { mIsTainted = aIsTainted; }
+
+  void SetInputPrimitive(size_t aInputIndex, int32_t aInputPrimitiveIndex) {
+    mInputPrimitives.EnsureLengthAtLeast(aInputIndex + 1);
+    mInputPrimitives[aInputIndex] = aInputPrimitiveIndex;
+  }
+
+  void SetInputColorSpace(size_t aInputIndex, ColorSpace aColorSpace) {
+    mInputColorSpaces.EnsureLengthAtLeast(aInputIndex + 1);
+    mInputColorSpaces[aInputIndex] = aColorSpace;
+  }
+
+  void SetOutputColorSpace(const ColorSpace& aColorSpace) {
+    mOutputColorSpace = aColorSpace;
+  }
+
+  bool operator==(const FilterPrimitiveDescription& aOther) const;
+  bool operator!=(const FilterPrimitiveDescription& aOther) const {
+    return !(*this == aOther);
+  }
+
+ private:
+  PrimitiveAttributes mAttributes;
+  AutoTArray<int32_t, 2> mInputPrimitives;
+  IntRect mFilterPrimitiveSubregion;
+  IntRect mFilterSpaceBounds;
+  AutoTArray<ColorSpace, 2> mInputColorSpaces;
+  ColorSpace mOutputColorSpace;
+  bool mIsTainted;
+};
+
+/**
+ * A data structure that contains one or more FilterPrimitiveDescriptions.
+ * Designed to be serializable via IPDL, so it must not contain complex
+ * functionality.
+ */
+struct FilterDescription final {
+  FilterDescription() = default;
+  explicit FilterDescription(nsTArray<FilterPrimitiveDescription>&& aPrimitives)
+      : mPrimitives(std::move(aPrimitives)) {}
+
+  bool operator==(const FilterDescription& aOther) const;
+  bool operator!=(const FilterDescription& aOther) const {
+    return !(*this == aOther);
+  }
+
+  CopyableTArray<FilterPrimitiveDescription> mPrimitives;
+};
+}  // namespace mozilla::gfx
+
+#endif  // __FilterSupport_h
diff --git a/gfx/src/FilterSupport.cpp b/gfx/src/FilterSupport.cpp
new file mode 100644
index 0000000000..36facacd73
--- /dev/null
+++ b/gfx/src/FilterSupport.cpp
@@ -0,0 +1,1953 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FilterSupport.h"
+#include "FilterDescription.h"
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Filters.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/PodOperations.h"
+
+#include "gfxContext.h"
+#include "gfxPattern.h"
+#include "gfxPlatform.h"
+#include "gfxUtils.h"
+#include "gfx2DGlue.h"
+
+#include "nsMargin.h"
+
+// c = n / 255
+// c <= 0.0031308f ? c * 12.92f : 1.055f * powf(c, 1 / 2.4f) - 0.055f
+static const float glinearRGBTosRGBMap[256] = {
+    0.000f, 0.050f, 0.085f, 0.111f, 0.132f, 0.150f, 0.166f, 0.181f, 0.194f,
+    0.207f, 0.219f, 0.230f, 0.240f, 0.250f, 0.260f, 0.269f, 0.278f, 0.286f,
+    0.295f, 0.303f, 0.310f, 0.318f, 0.325f, 0.332f, 0.339f, 0.346f, 0.352f,
+    0.359f, 0.365f, 0.371f, 0.378f, 0.383f, 0.389f, 0.395f, 0.401f, 0.406f,
+    0.412f, 0.417f, 0.422f, 0.427f, 0.433f, 0.438f, 0.443f, 0.448f, 0.452f,
+    0.457f, 0.462f, 0.466f, 0.471f, 0.476f, 0.480f, 0.485f, 0.489f, 0.493f,
+    0.498f, 0.502f, 0.506f, 0.510f, 0.514f, 0.518f, 0.522f, 0.526f, 0.530f,
+    0.534f, 0.538f, 0.542f, 0.546f, 0.549f, 0.553f, 0.557f, 0.561f, 0.564f,
+    0.568f, 0.571f, 0.575f, 0.579f, 0.582f, 0.586f, 0.589f, 0.592f, 0.596f,
+    0.599f, 0.603f, 0.606f, 0.609f, 0.613f, 0.616f, 0.619f, 0.622f, 0.625f,
+    0.629f, 0.632f, 0.635f, 0.638f, 0.641f, 0.644f, 0.647f, 0.650f, 0.653f,
+    0.656f, 0.659f, 0.662f, 0.665f, 0.668f, 0.671f, 0.674f, 0.677f, 0.680f,
+    0.683f, 0.685f, 0.688f, 0.691f, 0.694f, 0.697f, 0.699f, 0.702f, 0.705f,
+    0.708f, 0.710f, 0.713f, 0.716f, 0.718f, 0.721f, 0.724f, 0.726f, 0.729f,
+    0.731f, 0.734f, 0.737f, 0.739f, 0.742f, 0.744f, 0.747f, 0.749f, 0.752f,
+    0.754f, 0.757f, 0.759f, 0.762f, 0.764f, 0.767f, 0.769f, 0.772f, 0.774f,
+    0.776f, 0.779f, 0.781f, 0.784f, 0.786f, 0.788f, 0.791f, 0.793f, 0.795f,
+    0.798f, 0.800f, 0.802f, 0.805f, 0.807f, 0.809f, 0.812f, 0.814f, 0.816f,
+    0.818f, 0.821f, 0.823f, 0.825f, 0.827f, 0.829f, 0.832f, 0.834f, 0.836f,
+    0.838f, 0.840f, 0.843f, 0.845f, 0.847f, 0.849f, 0.851f, 0.853f, 0.855f,
+    0.857f, 0.860f, 0.862f, 0.864f, 0.866f, 0.868f, 0.870f, 0.872f, 0.874f,
+    0.876f, 0.878f, 0.880f, 0.882f, 0.884f, 0.886f, 0.888f, 0.890f, 0.892f,
+    0.894f, 0.896f, 0.898f, 0.900f, 0.902f, 0.904f, 0.906f, 0.908f, 0.910f,
+    0.912f, 0.914f, 0.916f, 0.918f, 0.920f, 0.922f, 0.924f, 0.926f, 0.928f,
+    0.930f, 0.931f, 0.933f, 0.935f, 0.937f, 0.939f, 0.941f, 0.943f, 0.945f,
+    0.946f, 0.948f, 0.950f, 0.952f, 0.954f, 0.956f, 0.957f, 0.959f, 0.961f,
+    0.963f, 0.965f, 0.967f, 0.968f, 0.970f, 0.972f, 0.974f, 0.975f, 0.977f,
+    0.979f, 0.981f, 0.983f, 0.984f, 0.986f, 0.988f, 0.990f, 0.991f, 0.993f,
+    0.995f, 0.997f, 0.998f, 1.000f};
+
+// c = n / 255
+// c <= 0.04045f ? c / 12.92f : powf((c + 0.055f) / 1.055f, 2.4f)
+extern const float gsRGBToLinearRGBMap[256] = {
+    0.000f, 0.000f, 0.001f, 0.001f, 0.001f, 0.002f, 0.002f, 0.002f, 0.002f,
+    0.003f, 0.003f, 0.003f, 0.004f, 0.004f, 0.004f, 0.005f, 0.005f, 0.006f,
+    0.006f, 0.007f, 0.007f, 0.007f, 0.008f, 0.009f, 0.009f, 0.010f, 0.010f,
+    0.011f, 0.012f, 0.012f, 0.013f, 0.014f, 0.014f, 0.015f, 0.016f, 0.017f,
+    0.018f, 0.019f, 0.019f, 0.020f, 0.021f, 0.022f, 0.023f, 0.024f, 0.025f,
+    0.026f, 0.027f, 0.028f, 0.030f, 0.031f, 0.032f, 0.033f, 0.034f, 0.036f,
+    0.037f, 0.038f, 0.040f, 0.041f, 0.042f, 0.044f, 0.045f, 0.047f, 0.048f,
+    0.050f, 0.051f, 0.053f, 0.054f, 0.056f, 0.058f, 0.060f, 0.061f, 0.063f,
+    0.065f, 0.067f, 0.068f, 0.070f, 0.072f, 0.074f, 0.076f, 0.078f, 0.080f,
+    0.082f, 0.084f, 0.087f, 0.089f, 0.091f, 0.093f, 0.095f, 0.098f, 0.100f,
+    0.102f, 0.105f, 0.107f, 0.109f, 0.112f, 0.114f, 0.117f, 0.120f, 0.122f,
+    0.125f, 0.127f, 0.130f, 0.133f, 0.136f, 0.138f, 0.141f, 0.144f, 0.147f,
+    0.150f, 0.153f, 0.156f, 0.159f, 0.162f, 0.165f, 0.168f, 0.171f, 0.175f,
+    0.178f, 0.181f, 0.184f, 0.188f, 0.191f, 0.195f, 0.198f, 0.202f, 0.205f,
+    0.209f, 0.212f, 0.216f, 0.220f, 0.223f, 0.227f, 0.231f, 0.235f, 0.238f,
+    0.242f, 0.246f, 0.250f, 0.254f, 0.258f, 0.262f, 0.266f, 0.270f, 0.275f,
+    0.279f, 0.283f, 0.287f, 0.292f, 0.296f, 0.301f, 0.305f, 0.309f, 0.314f,
+    0.319f, 0.323f, 0.328f, 0.332f, 0.337f, 0.342f, 0.347f, 0.352f, 0.356f,
+    0.361f, 0.366f, 0.371f, 0.376f, 0.381f, 0.386f, 0.392f, 0.397f, 0.402f,
+    0.407f, 0.413f, 0.418f, 0.423f, 0.429f, 0.434f, 0.440f, 0.445f, 0.451f,
+    0.456f, 0.462f, 0.468f, 0.474f, 0.479f, 0.485f, 0.491f, 0.497f, 0.503f,
+    0.509f, 0.515f, 0.521f, 0.527f, 0.533f, 0.539f, 0.546f, 0.552f, 0.558f,
+    0.565f, 0.571f, 0.578f, 0.584f, 0.591f, 0.597f, 0.604f, 0.610f, 0.617f,
+    0.624f, 0.631f, 0.638f, 0.644f, 0.651f, 0.658f, 0.665f, 0.672f, 0.680f,
+    0.687f, 0.694f, 0.701f, 0.708f, 0.716f, 0.723f, 0.730f, 0.738f, 0.745f,
+    0.753f, 0.761f, 0.768f, 0.776f, 0.784f, 0.791f, 0.799f, 0.807f, 0.815f,
+    0.823f, 0.831f, 0.839f, 0.847f, 0.855f, 0.863f, 0.871f, 0.880f, 0.888f,
+    0.896f, 0.905f, 0.913f, 0.922f, 0.930f, 0.939f, 0.947f, 0.956f, 0.965f,
+    0.973f, 0.982f, 0.991f, 1.000f};
+
+namespace mozilla {
+namespace gfx {
+
+// Some convenience FilterNode creation functions.
+
+namespace FilterWrappers {
+
+static already_AddRefed<FilterNode> Unpremultiply(DrawTarget* aDT,
+                                                  FilterNode* aInput) {
+  RefPtr<FilterNode> filter = aDT->CreateFilter(FilterType::UNPREMULTIPLY);
+  if (filter) {
+    filter->SetInput(IN_UNPREMULTIPLY_IN, aInput);
+    return filter.forget();
+  }
+  return nullptr;
+}
+
+static already_AddRefed<FilterNode> Premultiply(DrawTarget* aDT,
+                                                FilterNode* aInput) {
+  RefPtr<FilterNode> filter = aDT->CreateFilter(FilterType::PREMULTIPLY);
+  if (filter) {
+    filter->SetInput(IN_PREMULTIPLY_IN, aInput);
+    return filter.forget();
+  }
+  return nullptr;
+}
+
+static already_AddRefed<FilterNode> LinearRGBToSRGB(DrawTarget* aDT,
+                                                    FilterNode* aInput) {
+  RefPtr<FilterNode> transfer =
+      aDT->CreateFilter(FilterType::DISCRETE_TRANSFER);
+  if (transfer) {
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_R, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_R, glinearRGBTosRGBMap,
+                           256);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_G, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_G, glinearRGBTosRGBMap,
+                           256);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_B, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_B, glinearRGBTosRGBMap,
+                           256);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_A, true);
+    transfer->SetInput(IN_DISCRETE_TRANSFER_IN, aInput);
+    return transfer.forget();
+  }
+  return nullptr;
+}
+
+static already_AddRefed<FilterNode> SRGBToLinearRGB(DrawTarget* aDT,
+                                                    FilterNode* aInput) {
+  RefPtr<FilterNode> transfer =
+      aDT->CreateFilter(FilterType::DISCRETE_TRANSFER);
+  if (transfer) {
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_R, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_R, gsRGBToLinearRGBMap,
+                           256);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_G, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_G, gsRGBToLinearRGBMap,
+                           256);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_B, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_B, gsRGBToLinearRGBMap,
+                           256);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_A, true);
+    transfer->SetInput(IN_DISCRETE_TRANSFER_IN, aInput);
+    return transfer.forget();
+  }
+  return nullptr;
+}
+
+static already_AddRefed<FilterNode> Crop(DrawTarget* aDT,
+                                         FilterNode* aInputFilter,
+                                         const IntRect& aRect) {
+  RefPtr<FilterNode> filter = aDT->CreateFilter(FilterType::CROP);
+  if (filter) {
+    filter->SetAttribute(ATT_CROP_RECT, Rect(aRect));
+    filter->SetInput(IN_CROP_IN, aInputFilter);
+    return filter.forget();
+  }
+  return nullptr;
+}
+
+static already_AddRefed<FilterNode> Offset(DrawTarget* aDT,
+                                           FilterNode* aInputFilter,
+                                           const IntPoint& aOffset) {
+  RefPtr<FilterNode> filter = aDT->CreateFilter(FilterType::TRANSFORM);
+  if (filter) {
+    filter->SetAttribute(ATT_TRANSFORM_MATRIX,
+                         Matrix::Translation(aOffset.x, aOffset.y));
+    filter->SetInput(IN_TRANSFORM_IN, aInputFilter);
+    return filter.forget();
+  }
+  return nullptr;
+}
+
+static already_AddRefed<FilterNode> GaussianBlur(DrawTarget* aDT,
+                                                 FilterNode* aInputFilter,
+                                                 const Size& aStdDeviation) {
+  float stdX = float(std::min(aStdDeviation.width, kMaxStdDeviation));
+  float stdY = float(std::min(aStdDeviation.height, kMaxStdDeviation));
+  if (stdX == stdY) {
+    RefPtr<FilterNode> filter = aDT->CreateFilter(FilterType::GAUSSIAN_BLUR);
+    if (filter) {
+      filter->SetAttribute(ATT_GAUSSIAN_BLUR_STD_DEVIATION, stdX);
+      filter->SetInput(IN_GAUSSIAN_BLUR_IN, aInputFilter);
+      return filter.forget();
+    }
+    return nullptr;
+  }
+  RefPtr<FilterNode> filterH = aDT->CreateFilter(FilterType::DIRECTIONAL_BLUR);
+  RefPtr<FilterNode> filterV = aDT->CreateFilter(FilterType::DIRECTIONAL_BLUR);
+  if (filterH && filterV) {
+    filterH->SetAttribute(ATT_DIRECTIONAL_BLUR_DIRECTION,
+                          (uint32_t)BLUR_DIRECTION_X);
+    filterH->SetAttribute(ATT_DIRECTIONAL_BLUR_STD_DEVIATION, stdX);
+    filterV->SetAttribute(ATT_DIRECTIONAL_BLUR_DIRECTION,
+                          (uint32_t)BLUR_DIRECTION_Y);
+    filterV->SetAttribute(ATT_DIRECTIONAL_BLUR_STD_DEVIATION, stdY);
+    filterH->SetInput(IN_DIRECTIONAL_BLUR_IN, aInputFilter);
+    filterV->SetInput(IN_DIRECTIONAL_BLUR_IN, filterH);
+    return filterV.forget();
+  }
+  return nullptr;
+}
+
+already_AddRefed<FilterNode> Clear(DrawTarget* aDT) {
+  RefPtr<FilterNode> filter = aDT->CreateFilter(FilterType::FLOOD);
+  if (filter) {
+    filter->SetAttribute(ATT_FLOOD_COLOR, DeviceColor());
+    return filter.forget();
+  }
+  return nullptr;
+}
+
+already_AddRefed<FilterNode> ForSurface(DrawTarget* aDT,
+                                        SourceSurface* aSurface,
+                                        const IntPoint& aSurfacePosition) {
+  RefPtr<FilterNode> filter = aDT->CreateFilter(FilterType::TRANSFORM);
+  if (filter) {
+    filter->SetAttribute(
+        ATT_TRANSFORM_MATRIX,
+        Matrix::Translation(aSurfacePosition.x, aSurfacePosition.y));
+    filter->SetInput(IN_TRANSFORM_IN, aSurface);
+    return filter.forget();
+  }
+  return nullptr;
+}
+
+static already_AddRefed<FilterNode> ToAlpha(DrawTarget* aDT,
+                                            FilterNode* aInput) {
+  float zero = 0.0f;
+  RefPtr<FilterNode> transfer =
+      aDT->CreateFilter(FilterType::DISCRETE_TRANSFER);
+  if (transfer) {
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_R, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_R, &zero, 1);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_G, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_G, &zero, 1);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_B, false);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_TABLE_B, &zero, 1);
+    transfer->SetAttribute(ATT_DISCRETE_TRANSFER_DISABLE_A, true);
+    transfer->SetInput(IN_DISCRETE_TRANSFER_IN, aInput);
+    return transfer.forget();
+  }
+  return nullptr;
+}
+
+}  // namespace FilterWrappers
+
+// A class that wraps a FilterNode and handles conversion between different
+// color models. Create FilterCachedColorModels with your original filter and
+// the color model that this filter outputs in natively, and then call
+// ->ForColorModel(colorModel) in order to get a FilterNode which outputs to
+// the specified colorModel.
+// Internally, this is achieved by wrapping the original FilterNode with
+// conversion FilterNodes. These filter nodes are cached in such a way that no
+// repeated or back-and-forth conversions happen.
+class FilterCachedColorModels {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(FilterCachedColorModels)
+  // aFilter can be null. In that case, ForColorModel will return a non-null
+  // completely transparent filter for all color models.
+  FilterCachedColorModels(DrawTarget* aDT, FilterNode* aFilter,
+                          ColorModel aOriginalColorModel);
+
+  // Get a FilterNode for the specified color model, guaranteed to be non-null.
+  already_AddRefed<FilterNode> ForColorModel(ColorModel aColorModel);
+
+  AlphaModel OriginalAlphaModel() const {
+    return mOriginalColorModel.mAlphaModel;
+  }
+
+ private:
+  // Create the required FilterNode that will be cached by ForColorModel.
+  already_AddRefed<FilterNode> WrapForColorModel(ColorModel aColorModel);
+
+  RefPtr<DrawTarget> mDT;
+  ColorModel mOriginalColorModel;
+
+  // This array is indexed by ColorModel::ToIndex.
+  RefPtr<FilterNode> mFilterForColorModel[4];
+
+  ~FilterCachedColorModels() = default;
+};
+
+FilterCachedColorModels::FilterCachedColorModels(DrawTarget* aDT,
+                                                 FilterNode* aFilter,
+                                                 ColorModel aOriginalColorModel)
+    : mDT(aDT), mOriginalColorModel(aOriginalColorModel) {
+  if (aFilter) {
+    mFilterForColorModel[aOriginalColorModel.ToIndex()] = aFilter;
+  } else {
+    RefPtr<FilterNode> clear = FilterWrappers::Clear(aDT);
+    mFilterForColorModel[0] = clear;
+    mFilterForColorModel[1] = clear;
+    mFilterForColorModel[2] = clear;
+    mFilterForColorModel[3] = clear;
+  }
+}
+
+already_AddRefed<FilterNode> FilterCachedColorModels::ForColorModel(
+    ColorModel aColorModel) {
+  if (aColorModel == mOriginalColorModel) {
+    // Make sure to not call WrapForColorModel if our original filter node was
+    // null, because then we'd get an infinite recursion.
+    RefPtr<FilterNode> filter =
+        mFilterForColorModel[mOriginalColorModel.ToIndex()];
+    return filter.forget();
+  }
+
+  if (!mFilterForColorModel[aColorModel.ToIndex()]) {
+    mFilterForColorModel[aColorModel.ToIndex()] =
+        WrapForColorModel(aColorModel);
+  }
+  RefPtr<FilterNode> filter(mFilterForColorModel[aColorModel.ToIndex()]);
+  return filter.forget();
+}
+
+already_AddRefed<FilterNode> FilterCachedColorModels::WrapForColorModel(
+    ColorModel aColorModel) {
+  // Convert one aspect at a time and recurse.
+  // Conversions between premultiplied / unpremultiplied color channels for the
+  // same color space can happen directly.
+  // Conversions between different color spaces can only happen on
+  // unpremultiplied color channels.
+
+  if (aColorModel.mAlphaModel == AlphaModel::Premultiplied) {
+    RefPtr<FilterNode> unpre = ForColorModel(
+        ColorModel(aColorModel.mColorSpace, AlphaModel::Unpremultiplied));
+    return FilterWrappers::Premultiply(mDT, unpre);
+  }
+
+  MOZ_ASSERT(aColorModel.mAlphaModel == AlphaModel::Unpremultiplied);
+  if (aColorModel.mColorSpace == mOriginalColorModel.mColorSpace) {
+    RefPtr<FilterNode> premultiplied = ForColorModel(
+        ColorModel(aColorModel.mColorSpace, AlphaModel::Premultiplied));
+    return FilterWrappers::Unpremultiply(mDT, premultiplied);
+  }
+
+  RefPtr<FilterNode> unpremultipliedOriginal = ForColorModel(
+      ColorModel(mOriginalColorModel.mColorSpace, AlphaModel::Unpremultiplied));
+  if (aColorModel.mColorSpace == ColorSpace::LinearRGB) {
+    return FilterWrappers::SRGBToLinearRGB(mDT, unpremultipliedOriginal);
+  }
+  return FilterWrappers::LinearRGBToSRGB(mDT, unpremultipliedOriginal);
+}
+
+static const float identityMatrix[] = {1, 0, 0, 0, 0, 0, 1, 0, 0, 0,
+                                       0, 0, 1, 0, 0, 0, 0, 0, 1, 0};
+
+// When aAmount == 0, the identity matrix is returned.
+// When aAmount == 1, aToMatrix is returned.
+// When aAmount > 1, an exaggerated version of aToMatrix is returned. This can
+// be useful in certain cases, such as producing a color matrix to oversaturate
+// an image.
+//
+// This function is a shortcut of a full matrix addition and a scalar multiply,
+// and it assumes that the following elements in aToMatrix are 0 and 1:
+//   x x x 0 0
+//   x x x 0 0
+//   x x x 0 0
+//   0 0 0 1 0
+static void InterpolateFromIdentityMatrix(const float aToMatrix[20],
+                                          float aAmount, float aOutMatrix[20]) {
+  PodCopy(aOutMatrix, identityMatrix, 20);
+
+  float oneMinusAmount = 1 - aAmount;
+
+  aOutMatrix[0] = aAmount * aToMatrix[0] + oneMinusAmount;
+  aOutMatrix[1] = aAmount * aToMatrix[1];
+  aOutMatrix[2] = aAmount * aToMatrix[2];
+
+  aOutMatrix[5] = aAmount * aToMatrix[5];
+  aOutMatrix[6] = aAmount * aToMatrix[6] + oneMinusAmount;
+  aOutMatrix[7] = aAmount * aToMatrix[7];
+
+  aOutMatrix[10] = aAmount * aToMatrix[10];
+  aOutMatrix[11] = aAmount * aToMatrix[11];
+  aOutMatrix[12] = aAmount * aToMatrix[12] + oneMinusAmount;
+}
+
+// Create a 4x5 color matrix for the different ways to specify color matrices
+// in SVG.
+bool ComputeColorMatrix(const ColorMatrixAttributes& aMatrixAttributes,
+                        float aOutMatrix[20]) {
+  // Luminance coefficients.
+  static const float lumR = 0.2126f;
+  static const float lumG = 0.7152f;
+  static const float lumB = 0.0722f;
+
+  static const float oneMinusLumR = 1 - lumR;
+  static const float oneMinusLumG = 1 - lumG;
+  static const float oneMinusLumB = 1 - lumB;
+
+  static const float luminanceToAlphaMatrix[] = {
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, lumR, lumG, lumB, 0, 0};
+
+  static const float saturateMatrix[] = {
+      lumR, lumG, lumB, 0, 0, lumR, lumG, lumB, 0, 0,
+      lumR, lumG, lumB, 0, 0, 0,    0,    0,    1, 0};
+
+  static const float sepiaMatrix[] = {
+      0.393f, 0.769f, 0.189f, 0, 0, 0.349f, 0.686f, 0.168f, 0, 0,
+      0.272f, 0.534f, 0.131f, 0, 0, 0,      0,      0,      1, 0};
+
+  // Hue rotate specific coefficients.
+  static const float hueRotateR = 0.143f;
+  static const float hueRotateG = 0.140f;
+  static const float hueRotateB = 0.283f;
+
+  switch (aMatrixAttributes.mType) {
+    case SVG_FECOLORMATRIX_TYPE_MATRIX: {
+      if (aMatrixAttributes.mValues.Length() != 20) {
+        return false;
+      }
+
+      PodCopy(aOutMatrix, aMatrixAttributes.mValues.Elements(), 20);
+      break;
+    }
+
+    case SVG_FECOLORMATRIX_TYPE_SATURATE: {
+      if (aMatrixAttributes.mValues.Length() != 1) {
+        return false;
+      }
+
+      float s = aMatrixAttributes.mValues[0];
+
+      if (s < 0) {
+        return false;
+      }
+
+      InterpolateFromIdentityMatrix(saturateMatrix, 1 - s, aOutMatrix);
+      break;
+    }
+
+    case SVG_FECOLORMATRIX_TYPE_HUE_ROTATE: {
+      if (aMatrixAttributes.mValues.Length() != 1) {
+        return false;
+      }
+
+      PodCopy(aOutMatrix, identityMatrix, 20);
+
+      float hueRotateValue = aMatrixAttributes.mValues[0];
+
+      float c = static_cast<float>(cos(hueRotateValue * M_PI / 180));
+      float s = static_cast<float>(sin(hueRotateValue * M_PI / 180));
+
+      aOutMatrix[0] = lumR + oneMinusLumR * c - lumR * s;
+      aOutMatrix[1] = lumG - lumG * c - lumG * s;
+      aOutMatrix[2] = lumB - lumB * c + oneMinusLumB * s;
+
+      aOutMatrix[5] = lumR - lumR * c + hueRotateR * s;
+      aOutMatrix[6] = lumG + oneMinusLumG * c + hueRotateG * s;
+      aOutMatrix[7] = lumB - lumB * c - hueRotateB * s;
+
+      aOutMatrix[10] = lumR - lumR * c - oneMinusLumR * s;
+      aOutMatrix[11] = lumG - lumG * c + lumG * s;
+      aOutMatrix[12] = lumB + oneMinusLumB * c + lumB * s;
+
+      break;
+    }
+
+    case SVG_FECOLORMATRIX_TYPE_LUMINANCE_TO_ALPHA: {
+      PodCopy(aOutMatrix, luminanceToAlphaMatrix, 20);
+      break;
+    }
+
+    case SVG_FECOLORMATRIX_TYPE_SEPIA: {
+      if (aMatrixAttributes.mValues.Length() != 1) {
+        return false;
+      }
+
+      float amount = aMatrixAttributes.mValues[0];
+
+      if (amount < 0 || amount > 1) {
+        return false;
+      }
+
+      InterpolateFromIdentityMatrix(sepiaMatrix, amount, aOutMatrix);
+      break;
+    }
+
+    default: {
+      return false;
+    }
+  }
+
+  return !ArrayEqual(aOutMatrix, identityMatrix, 20);
+}
+
+static void DisableAllTransfers(FilterNode* aTransferFilterNode) {
+  aTransferFilterNode->SetAttribute(ATT_TRANSFER_DISABLE_R, true);
+  aTransferFilterNode->SetAttribute(ATT_TRANSFER_DISABLE_G, true);
+  aTransferFilterNode->SetAttribute(ATT_TRANSFER_DISABLE_B, true);
+  aTransferFilterNode->SetAttribute(ATT_TRANSFER_DISABLE_A, true);
+}
+
+// Called for one channel at a time.
+// This function creates the required FilterNodes on demand and tries to
+// merge conversions of different channels into the same FilterNode if
+// possible.
+// There's a mismatch between the way SVG and the Moz2D API handle transfer
+// functions: In SVG, it's possible to specify a different transfer function
+// type for each color channel, but in Moz2D, a given transfer function type
+// applies to all color channels.
+//
+//  @param aFunctionAttributes The attributes of the transfer function for this
+//                             channel.
+//  @param aChannel The color channel that this function applies to, where
+//                  0 = red, 1 = green, 2 = blue, 3 = alpha
+//  @param aDT The DrawTarget that the FilterNodes should be created for.
+//  @param aTableTransfer Existing FilterNode holders (which may still be
+//                        null) that the resulting FilterNodes from this
+//                        function will be stored in.
+//
+static void ConvertComponentTransferFunctionToFilter(
+    const ComponentTransferAttributes& aFunctionAttributes, int32_t aInChannel,
+    int32_t aOutChannel, DrawTarget* aDT, RefPtr<FilterNode>& aTableTransfer,
+    RefPtr<FilterNode>& aDiscreteTransfer, RefPtr<FilterNode>& aLinearTransfer,
+    RefPtr<FilterNode>& aGammaTransfer) {
+  static const TransferAtts disableAtt[4] = {
+      ATT_TRANSFER_DISABLE_R, ATT_TRANSFER_DISABLE_G, ATT_TRANSFER_DISABLE_B,
+      ATT_TRANSFER_DISABLE_A};
+
+  RefPtr<FilterNode> filter;
+
+  uint32_t type = aFunctionAttributes.mTypes[aInChannel];
+
+  switch (type) {
+    case SVG_FECOMPONENTTRANSFER_TYPE_TABLE: {
+      const nsTArray<float>& tableValues =
+          aFunctionAttributes.mValues[aInChannel];
+      if (tableValues.Length() < 2) return;
+
+      if (!aTableTransfer) {
+        aTableTransfer = aDT->CreateFilter(FilterType::TABLE_TRANSFER);
+        if (!aTableTransfer) {
+          return;
+        }
+        DisableAllTransfers(aTableTransfer);
+      }
+      filter = aTableTransfer;
+      static const TableTransferAtts tableAtt[4] = {
+          ATT_TABLE_TRANSFER_TABLE_R, ATT_TABLE_TRANSFER_TABLE_G,
+          ATT_TABLE_TRANSFER_TABLE_B, ATT_TABLE_TRANSFER_TABLE_A};
+      filter->SetAttribute(disableAtt[aOutChannel], false);
+      filter->SetAttribute(tableAtt[aOutChannel], &tableValues[0],
+                           tableValues.Length());
+      break;
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_DISCRETE: {
+      const nsTArray<float>& tableValues =
+          aFunctionAttributes.mValues[aInChannel];
+      if (tableValues.Length() < 1) return;
+
+      if (!aDiscreteTransfer) {
+        aDiscreteTransfer = aDT->CreateFilter(FilterType::DISCRETE_TRANSFER);
+        if (!aDiscreteTransfer) {
+          return;
+        }
+        DisableAllTransfers(aDiscreteTransfer);
+      }
+      filter = aDiscreteTransfer;
+      static const DiscreteTransferAtts tableAtt[4] = {
+          ATT_DISCRETE_TRANSFER_TABLE_R, ATT_DISCRETE_TRANSFER_TABLE_G,
+          ATT_DISCRETE_TRANSFER_TABLE_B, ATT_DISCRETE_TRANSFER_TABLE_A};
+      filter->SetAttribute(disableAtt[aOutChannel], false);
+      filter->SetAttribute(tableAtt[aOutChannel], &tableValues[0],
+                           tableValues.Length());
+
+      break;
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_LINEAR: {
+      static const LinearTransferAtts slopeAtt[4] = {
+          ATT_LINEAR_TRANSFER_SLOPE_R, ATT_LINEAR_TRANSFER_SLOPE_G,
+          ATT_LINEAR_TRANSFER_SLOPE_B, ATT_LINEAR_TRANSFER_SLOPE_A};
+      static const LinearTransferAtts interceptAtt[4] = {
+          ATT_LINEAR_TRANSFER_INTERCEPT_R, ATT_LINEAR_TRANSFER_INTERCEPT_G,
+          ATT_LINEAR_TRANSFER_INTERCEPT_B, ATT_LINEAR_TRANSFER_INTERCEPT_A};
+      if (!aLinearTransfer) {
+        aLinearTransfer = aDT->CreateFilter(FilterType::LINEAR_TRANSFER);
+        if (!aLinearTransfer) {
+          return;
+        }
+        DisableAllTransfers(aLinearTransfer);
+      }
+      filter = aLinearTransfer;
+      filter->SetAttribute(disableAtt[aOutChannel], false);
+      const nsTArray<float>& slopeIntercept =
+          aFunctionAttributes.mValues[aInChannel];
+      float slope = slopeIntercept[kComponentTransferSlopeIndex];
+      float intercept = slopeIntercept[kComponentTransferInterceptIndex];
+      filter->SetAttribute(slopeAtt[aOutChannel], slope);
+      filter->SetAttribute(interceptAtt[aOutChannel], intercept);
+      break;
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_GAMMA: {
+      static const GammaTransferAtts amplitudeAtt[4] = {
+          ATT_GAMMA_TRANSFER_AMPLITUDE_R, ATT_GAMMA_TRANSFER_AMPLITUDE_G,
+          ATT_GAMMA_TRANSFER_AMPLITUDE_B, ATT_GAMMA_TRANSFER_AMPLITUDE_A};
+      static const GammaTransferAtts exponentAtt[4] = {
+          ATT_GAMMA_TRANSFER_EXPONENT_R, ATT_GAMMA_TRANSFER_EXPONENT_G,
+          ATT_GAMMA_TRANSFER_EXPONENT_B, ATT_GAMMA_TRANSFER_EXPONENT_A};
+      static const GammaTransferAtts offsetAtt[4] = {
+          ATT_GAMMA_TRANSFER_OFFSET_R, ATT_GAMMA_TRANSFER_OFFSET_G,
+          ATT_GAMMA_TRANSFER_OFFSET_B, ATT_GAMMA_TRANSFER_OFFSET_A};
+      if (!aGammaTransfer) {
+        aGammaTransfer = aDT->CreateFilter(FilterType::GAMMA_TRANSFER);
+        if (!aGammaTransfer) {
+          return;
+        }
+        DisableAllTransfers(aGammaTransfer);
+      }
+      filter = aGammaTransfer;
+      filter->SetAttribute(disableAtt[aOutChannel], false);
+      const nsTArray<float>& gammaValues =
+          aFunctionAttributes.mValues[aInChannel];
+      float amplitude = gammaValues[kComponentTransferAmplitudeIndex];
+      float exponent = gammaValues[kComponentTransferExponentIndex];
+      float offset = gammaValues[kComponentTransferOffsetIndex];
+      filter->SetAttribute(amplitudeAtt[aOutChannel], amplitude);
+      filter->SetAttribute(exponentAtt[aOutChannel], exponent);
+      filter->SetAttribute(offsetAtt[aOutChannel], offset);
+      break;
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_IDENTITY:
+    default:
+      break;
+  }
+}
+
+const int32_t kMorphologyMaxRadius = 100000;
+
+// Handle the different primitive description types and create the necessary
+// FilterNode(s) for each.
+// Returns nullptr for invalid filter primitives. This should be interpreted as
+// transparent black by the caller.
+// aSourceRegions contains the filter primitive subregions of the source
+// primitives; only needed for eTile primitives.
+// aInputImages carries additional surfaces that are used by eImage primitives.
+static already_AddRefed<FilterNode> FilterNodeFromPrimitiveDescription(
+    const FilterPrimitiveDescription& aDescription, DrawTarget* aDT,
+    nsTArray<RefPtr<FilterNode>>& aSources, nsTArray<IntRect>& aSourceRegions,
+    nsTArray<RefPtr<SourceSurface>>& aInputImages) {
+  struct PrimitiveAttributesMatcher {
+    PrimitiveAttributesMatcher(const FilterPrimitiveDescription& aDescription,
+                               DrawTarget* aDT,
+                               nsTArray<RefPtr<FilterNode>>& aSources,
+                               nsTArray<IntRect>& aSourceRegions,
+                               nsTArray<RefPtr<SourceSurface>>& aInputImages)
+        : mDescription(aDescription),
+          mDT(aDT),
+          mSources(aSources),
+          mSourceRegions(aSourceRegions),
+          mInputImages(aInputImages) {}
+
+    const FilterPrimitiveDescription& mDescription;
+    DrawTarget* mDT;
+    nsTArray<RefPtr<FilterNode>>& mSources;
+    nsTArray<IntRect>& mSourceRegions;
+    nsTArray<RefPtr<SourceSurface>>& mInputImages;
+
+    already_AddRefed<FilterNode> operator()(
+        const EmptyAttributes& aEmptyAttributes) {
+      return nullptr;
+    }
+
+    already_AddRefed<FilterNode> operator()(const BlendAttributes& aBlend) {
+      uint32_t mode = aBlend.mBlendMode;
+      RefPtr<FilterNode> filter;
+      if (mode == SVG_FEBLEND_MODE_UNKNOWN) {
+        return nullptr;
+      }
+      if (mode == SVG_FEBLEND_MODE_NORMAL) {
+        filter = mDT->CreateFilter(FilterType::COMPOSITE);
+        if (!filter) {
+          return nullptr;
+        }
+        filter->SetInput(IN_COMPOSITE_IN_START, mSources[1]);
+        filter->SetInput(IN_COMPOSITE_IN_START + 1, mSources[0]);
+      } else {
+        filter = mDT->CreateFilter(FilterType::BLEND);
+        if (!filter) {
+          return nullptr;
+        }
+        static const uint8_t blendModes[SVG_FEBLEND_MODE_LUMINOSITY + 1] = {
+            0,
+            0,
+            BLEND_MODE_MULTIPLY,
+            BLEND_MODE_SCREEN,
+            BLEND_MODE_DARKEN,
+            BLEND_MODE_LIGHTEN,
+            BLEND_MODE_OVERLAY,
+            BLEND_MODE_COLOR_DODGE,
+            BLEND_MODE_COLOR_BURN,
+            BLEND_MODE_HARD_LIGHT,
+            BLEND_MODE_SOFT_LIGHT,
+            BLEND_MODE_DIFFERENCE,
+            BLEND_MODE_EXCLUSION,
+            BLEND_MODE_HUE,
+            BLEND_MODE_SATURATION,
+            BLEND_MODE_COLOR,
+            BLEND_MODE_LUMINOSITY};
+        filter->SetAttribute(ATT_BLEND_BLENDMODE, (uint32_t)blendModes[mode]);
+        // The correct input order for both software and D2D filters is flipped
+        // from our source order, so flip here.
+        filter->SetInput(IN_BLEND_IN, mSources[1]);
+        filter->SetInput(IN_BLEND_IN2, mSources[0]);
+      }
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const ColorMatrixAttributes& aMatrixAttributes) {
+      float colorMatrix[20];
+      if (!ComputeColorMatrix(aMatrixAttributes, colorMatrix)) {
+        RefPtr<FilterNode> filter(mSources[0]);
+        return filter.forget();
+      }
+
+      Matrix5x4 matrix(
+          colorMatrix[0], colorMatrix[5], colorMatrix[10], colorMatrix[15],
+          colorMatrix[1], colorMatrix[6], colorMatrix[11], colorMatrix[16],
+          colorMatrix[2], colorMatrix[7], colorMatrix[12], colorMatrix[17],
+          colorMatrix[3], colorMatrix[8], colorMatrix[13], colorMatrix[18],
+          colorMatrix[4], colorMatrix[9], colorMatrix[14], colorMatrix[19]);
+
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::COLOR_MATRIX);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_COLOR_MATRIX_MATRIX, matrix);
+      filter->SetAttribute(ATT_COLOR_MATRIX_ALPHA_MODE,
+                           (uint32_t)ALPHA_MODE_STRAIGHT);
+      filter->SetInput(IN_COLOR_MATRIX_IN, mSources[0]);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const MorphologyAttributes& aMorphology) {
+      Size radii = aMorphology.mRadii;
+      int32_t rx = radii.width;
+      int32_t ry = radii.height;
+
+      // Is one of the radii zero or negative, return the input image
+      if (rx <= 0 || ry <= 0) {
+        RefPtr<FilterNode> filter(mSources[0]);
+        return filter.forget();
+      }
+
+      // Clamp radii to prevent completely insane values:
+      rx = std::min(rx, kMorphologyMaxRadius);
+      ry = std::min(ry, kMorphologyMaxRadius);
+
+      MorphologyOperator op = aMorphology.mOperator == SVG_OPERATOR_ERODE
+                                  ? MORPHOLOGY_OPERATOR_ERODE
+                                  : MORPHOLOGY_OPERATOR_DILATE;
+
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::MORPHOLOGY);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_MORPHOLOGY_RADII, IntSize(rx, ry));
+      filter->SetAttribute(ATT_MORPHOLOGY_OPERATOR, (uint32_t)op);
+      filter->SetInput(IN_MORPHOLOGY_IN, mSources[0]);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(const FloodAttributes& aFlood) {
+      DeviceColor color = ToDeviceColor(aFlood.mColor);
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::FLOOD);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_FLOOD_COLOR, color);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(const TileAttributes& aTile) {
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::TILE);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_TILE_SOURCE_RECT, mSourceRegions[0]);
+      filter->SetInput(IN_TILE_IN, mSources[0]);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const ComponentTransferAttributes& aComponentTransfer) {
+      MOZ_ASSERT(aComponentTransfer.mTypes[0] !=
+                 SVG_FECOMPONENTTRANSFER_SAME_AS_R);
+      MOZ_ASSERT(aComponentTransfer.mTypes[3] !=
+                 SVG_FECOMPONENTTRANSFER_SAME_AS_R);
+
+      RefPtr<FilterNode> filters[4];  // one for each FILTER_*_TRANSFER type
+      for (int32_t i = 0; i < 4; i++) {
+        int32_t inputIndex = (aComponentTransfer.mTypes[i] ==
+                              SVG_FECOMPONENTTRANSFER_SAME_AS_R) &&
+                                     (i < 3)
+                                 ? 0
+                                 : i;
+        ConvertComponentTransferFunctionToFilter(aComponentTransfer, inputIndex,
+                                                 i, mDT, filters[0], filters[1],
+                                                 filters[2], filters[3]);
+      }
+
+      // Connect all used filters nodes.
+      RefPtr<FilterNode> lastFilter = mSources[0];
+      for (int32_t i = 0; i < 4; i++) {
+        if (filters[i]) {
+          filters[i]->SetInput(0, lastFilter);
+          lastFilter = filters[i];
+        }
+      }
+
+      return lastFilter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(const OpacityAttributes& aOpacity) {
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::OPACITY);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_OPACITY_VALUE, aOpacity.mOpacity);
+      filter->SetInput(IN_OPACITY_IN, mSources[0]);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const ConvolveMatrixAttributes& aConvolveMatrix) {
+      RefPtr<FilterNode> filter =
+          mDT->CreateFilter(FilterType::CONVOLVE_MATRIX);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_KERNEL_SIZE,
+                           aConvolveMatrix.mKernelSize);
+      const nsTArray<float>& matrix = aConvolveMatrix.mKernelMatrix;
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_KERNEL_MATRIX, matrix.Elements(),
+                           matrix.Length());
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_DIVISOR,
+                           aConvolveMatrix.mDivisor);
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_BIAS, aConvolveMatrix.mBias);
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_TARGET, aConvolveMatrix.mTarget);
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_SOURCE_RECT, mSourceRegions[0]);
+      uint32_t edgeMode = aConvolveMatrix.mEdgeMode;
+      static const uint8_t edgeModes[SVG_EDGEMODE_NONE + 1] = {
+          EDGE_MODE_NONE,       // SVG_EDGEMODE_UNKNOWN
+          EDGE_MODE_DUPLICATE,  // SVG_EDGEMODE_DUPLICATE
+          EDGE_MODE_WRAP,       // SVG_EDGEMODE_WRAP
+          EDGE_MODE_NONE        // SVG_EDGEMODE_NONE
+      };
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_EDGE_MODE,
+                           (uint32_t)edgeModes[edgeMode]);
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_KERNEL_UNIT_LENGTH,
+                           aConvolveMatrix.mKernelUnitLength);
+      filter->SetAttribute(ATT_CONVOLVE_MATRIX_PRESERVE_ALPHA,
+                           aConvolveMatrix.mPreserveAlpha);
+      filter->SetInput(IN_CONVOLVE_MATRIX_IN, mSources[0]);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(const OffsetAttributes& aOffset) {
+      return FilterWrappers::Offset(mDT, mSources[0], aOffset.mValue);
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const DisplacementMapAttributes& aDisplacementMap) {
+      RefPtr<FilterNode> filter =
+          mDT->CreateFilter(FilterType::DISPLACEMENT_MAP);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_DISPLACEMENT_MAP_SCALE, aDisplacementMap.mScale);
+      static const uint8_t channel[SVG_CHANNEL_A + 1] = {
+          COLOR_CHANNEL_R,  // SVG_CHANNEL_UNKNOWN
+          COLOR_CHANNEL_R,  // SVG_CHANNEL_R
+          COLOR_CHANNEL_G,  // SVG_CHANNEL_G
+          COLOR_CHANNEL_B,  // SVG_CHANNEL_B
+          COLOR_CHANNEL_A   // SVG_CHANNEL_A
+      };
+      filter->SetAttribute(ATT_DISPLACEMENT_MAP_X_CHANNEL,
+                           (uint32_t)channel[aDisplacementMap.mXChannel]);
+      filter->SetAttribute(ATT_DISPLACEMENT_MAP_Y_CHANNEL,
+                           (uint32_t)channel[aDisplacementMap.mYChannel]);
+      filter->SetInput(IN_DISPLACEMENT_MAP_IN, mSources[0]);
+      filter->SetInput(IN_DISPLACEMENT_MAP_IN2, mSources[1]);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const TurbulenceAttributes& aTurbulence) {
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::TURBULENCE);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_TURBULENCE_BASE_FREQUENCY,
+                           aTurbulence.mBaseFrequency);
+      filter->SetAttribute(ATT_TURBULENCE_NUM_OCTAVES, aTurbulence.mOctaves);
+      filter->SetAttribute(ATT_TURBULENCE_STITCHABLE, aTurbulence.mStitchable);
+      filter->SetAttribute(ATT_TURBULENCE_SEED, (uint32_t)aTurbulence.mSeed);
+      static const uint8_t type[SVG_TURBULENCE_TYPE_TURBULENCE + 1] = {
+          TURBULENCE_TYPE_FRACTAL_NOISE,  // SVG_TURBULENCE_TYPE_UNKNOWN
+          TURBULENCE_TYPE_FRACTAL_NOISE,  // SVG_TURBULENCE_TYPE_FRACTALNOISE
+          TURBULENCE_TYPE_TURBULENCE      // SVG_TURBULENCE_TYPE_TURBULENCE
+      };
+      filter->SetAttribute(ATT_TURBULENCE_TYPE,
+                           (uint32_t)type[aTurbulence.mType]);
+      filter->SetAttribute(
+          ATT_TURBULENCE_RECT,
+          mDescription.PrimitiveSubregion() - aTurbulence.mOffset);
+      return FilterWrappers::Offset(mDT, filter, aTurbulence.mOffset);
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const CompositeAttributes& aComposite) {
+      RefPtr<FilterNode> filter;
+      uint32_t op = aComposite.mOperator;
+      if (op == SVG_FECOMPOSITE_OPERATOR_ARITHMETIC) {
+        const nsTArray<float>& coefficients = aComposite.mCoefficients;
+        static const float allZero[4] = {0, 0, 0, 0};
+        filter = mDT->CreateFilter(FilterType::ARITHMETIC_COMBINE);
+        // All-zero coefficients sometimes occur in junk filters.
+        if (!filter || (coefficients.Length() == ArrayLength(allZero) &&
+                        ArrayEqual(coefficients.Elements(), allZero,
+                                   ArrayLength(allZero)))) {
+          return nullptr;
+        }
+        filter->SetAttribute(ATT_ARITHMETIC_COMBINE_COEFFICIENTS,
+                             coefficients.Elements(), coefficients.Length());
+        filter->SetInput(IN_ARITHMETIC_COMBINE_IN, mSources[0]);
+        filter->SetInput(IN_ARITHMETIC_COMBINE_IN2, mSources[1]);
+      } else {
+        filter = mDT->CreateFilter(FilterType::COMPOSITE);
+        if (!filter) {
+          return nullptr;
+        }
+        static const uint8_t operators[SVG_FECOMPOSITE_OPERATOR_LIGHTER + 1] = {
+            COMPOSITE_OPERATOR_OVER,    // SVG_FECOMPOSITE_OPERATOR_UNKNOWN
+            COMPOSITE_OPERATOR_OVER,    // SVG_FECOMPOSITE_OPERATOR_OVER
+            COMPOSITE_OPERATOR_IN,      // SVG_FECOMPOSITE_OPERATOR_IN
+            COMPOSITE_OPERATOR_OUT,     // SVG_FECOMPOSITE_OPERATOR_OUT
+            COMPOSITE_OPERATOR_ATOP,    // SVG_FECOMPOSITE_OPERATOR_ATOP
+            COMPOSITE_OPERATOR_XOR,     // SVG_FECOMPOSITE_OPERATOR_XOR
+            COMPOSITE_OPERATOR_OVER,    // Unused, arithmetic is handled above
+            COMPOSITE_OPERATOR_LIGHTER  // SVG_FECOMPOSITE_OPERATOR_LIGHTER
+        };
+        filter->SetAttribute(ATT_COMPOSITE_OPERATOR, (uint32_t)operators[op]);
+        filter->SetInput(IN_COMPOSITE_IN_START, mSources[1]);
+        filter->SetInput(IN_COMPOSITE_IN_START + 1, mSources[0]);
+      }
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(const MergeAttributes& aMerge) {
+      if (mSources.Length() == 0) {
+        return nullptr;
+      }
+      if (mSources.Length() == 1) {
+        RefPtr<FilterNode> filter(mSources[0]);
+        return filter.forget();
+      }
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::COMPOSITE);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_COMPOSITE_OPERATOR,
+                           (uint32_t)COMPOSITE_OPERATOR_OVER);
+      for (size_t i = 0; i < mSources.Length(); i++) {
+        filter->SetInput(IN_COMPOSITE_IN_START + i, mSources[i]);
+      }
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const GaussianBlurAttributes& aGaussianBlur) {
+      return FilterWrappers::GaussianBlur(mDT, mSources[0],
+                                          aGaussianBlur.mStdDeviation);
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const DropShadowAttributes& aDropShadow) {
+      RefPtr<FilterNode> alpha = FilterWrappers::ToAlpha(mDT, mSources[0]);
+      RefPtr<FilterNode> blur =
+          FilterWrappers::GaussianBlur(mDT, alpha, aDropShadow.mStdDeviation);
+      RefPtr<FilterNode> offsetBlur = FilterWrappers::Offset(
+          mDT, blur, IntPoint::Truncate(aDropShadow.mOffset));
+      RefPtr<FilterNode> flood = mDT->CreateFilter(FilterType::FLOOD);
+      if (!flood) {
+        return nullptr;
+      }
+      sRGBColor color = aDropShadow.mColor;
+      if (mDescription.InputColorSpace(0) == ColorSpace::LinearRGB) {
+        color = sRGBColor(gsRGBToLinearRGBMap[uint8_t(color.r * 255)],
+                          gsRGBToLinearRGBMap[uint8_t(color.g * 255)],
+                          gsRGBToLinearRGBMap[uint8_t(color.b * 255)], color.a);
+      }
+      flood->SetAttribute(ATT_FLOOD_COLOR, ToDeviceColor(color));
+
+      RefPtr<FilterNode> composite = mDT->CreateFilter(FilterType::COMPOSITE);
+      if (!composite) {
+        return nullptr;
+      }
+      composite->SetAttribute(ATT_COMPOSITE_OPERATOR,
+                              (uint32_t)COMPOSITE_OPERATOR_IN);
+      composite->SetInput(IN_COMPOSITE_IN_START, offsetBlur);
+      composite->SetInput(IN_COMPOSITE_IN_START + 1, flood);
+
+      RefPtr<FilterNode> filter = mDT->CreateFilter(FilterType::COMPOSITE);
+      if (!filter) {
+        return nullptr;
+      }
+      filter->SetAttribute(ATT_COMPOSITE_OPERATOR,
+                           (uint32_t)COMPOSITE_OPERATOR_OVER);
+      filter->SetInput(IN_COMPOSITE_IN_START, composite);
+      filter->SetInput(IN_COMPOSITE_IN_START + 1, mSources[0]);
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const SpecularLightingAttributes& aLighting) {
+      return operator()(
+          *(static_cast<const DiffuseLightingAttributes*>(&aLighting)));
+    }
+
+    already_AddRefed<FilterNode> operator()(
+        const DiffuseLightingAttributes& aLighting) {
+      bool isSpecular =
+          mDescription.Attributes().is<SpecularLightingAttributes>();
+
+      if (aLighting.mLightType == LightType::None) {
+        return nullptr;
+      }
+
+      enum { POINT = 0, SPOT, DISTANT } lightType = POINT;
+
+      switch (aLighting.mLightType) {
+        case LightType::Point:
+          lightType = POINT;
+          break;
+        case LightType::Spot:
+          lightType = SPOT;
+          break;
+        case LightType::Distant:
+          lightType = DISTANT;
+          break;
+        default:
+          break;
+      }
+
+      static const FilterType filterType[2][DISTANT + 1] = {
+          {FilterType::POINT_DIFFUSE, FilterType::SPOT_DIFFUSE,
+           FilterType::DISTANT_DIFFUSE},
+          {FilterType::POINT_SPECULAR, FilterType::SPOT_SPECULAR,
+           FilterType::DISTANT_SPECULAR}};
+      RefPtr<FilterNode> filter =
+          mDT->CreateFilter(filterType[isSpecular][lightType]);
+      if (!filter) {
+        return nullptr;
+      }
+
+      filter->SetAttribute(ATT_LIGHTING_COLOR, ToDeviceColor(aLighting.mColor));
+      filter->SetAttribute(ATT_LIGHTING_SURFACE_SCALE, aLighting.mSurfaceScale);
+      filter->SetAttribute(ATT_LIGHTING_KERNEL_UNIT_LENGTH,
+                           aLighting.mKernelUnitLength);
+
+      if (isSpecular) {
+        filter->SetAttribute(ATT_SPECULAR_LIGHTING_SPECULAR_CONSTANT,
+                             aLighting.mLightingConstant);
+        filter->SetAttribute(ATT_SPECULAR_LIGHTING_SPECULAR_EXPONENT,
+                             aLighting.mSpecularExponent);
+      } else {
+        filter->SetAttribute(ATT_DIFFUSE_LIGHTING_DIFFUSE_CONSTANT,
+                             aLighting.mLightingConstant);
+      }
+
+      switch (lightType) {
+        case POINT: {
+          Point3D position(aLighting.mLightValues[kPointLightPositionXIndex],
+                           aLighting.mLightValues[kPointLightPositionYIndex],
+                           aLighting.mLightValues[kPointLightPositionZIndex]);
+          filter->SetAttribute(ATT_POINT_LIGHT_POSITION, position);
+          break;
+        }
+        case SPOT: {
+          Point3D position(aLighting.mLightValues[kSpotLightPositionXIndex],
+                           aLighting.mLightValues[kSpotLightPositionYIndex],
+                           aLighting.mLightValues[kSpotLightPositionZIndex]);
+          filter->SetAttribute(ATT_SPOT_LIGHT_POSITION, position);
+          Point3D pointsAt(aLighting.mLightValues[kSpotLightPointsAtXIndex],
+                           aLighting.mLightValues[kSpotLightPointsAtYIndex],
+                           aLighting.mLightValues[kSpotLightPointsAtZIndex]);
+          filter->SetAttribute(ATT_SPOT_LIGHT_POINTS_AT, pointsAt);
+          filter->SetAttribute(ATT_SPOT_LIGHT_FOCUS,
+                               aLighting.mLightValues[kSpotLightFocusIndex]);
+          filter->SetAttribute(
+              ATT_SPOT_LIGHT_LIMITING_CONE_ANGLE,
+              aLighting.mLightValues[kSpotLightLimitingConeAngleIndex]);
+          break;
+        }
+        case DISTANT: {
+          filter->SetAttribute(
+              ATT_DISTANT_LIGHT_AZIMUTH,
+              aLighting.mLightValues[kDistantLightAzimuthIndex]);
+          filter->SetAttribute(
+              ATT_DISTANT_LIGHT_ELEVATION,
+              aLighting.mLightValues[kDistantLightElevationIndex]);
+          break;
+        }
+      }
+
+      filter->SetInput(IN_LIGHTING_IN, mSources[0]);
+
+      return filter.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(const ImageAttributes& aImage) {
+      const Matrix& TM = aImage.mTransform;
+      if (!TM.Determinant()) {
+        return nullptr;
+      }
+
+      // Pull the image from the additional image list using the index that's
+      // stored in the primitive description.
+      RefPtr<SourceSurface> inputImage = mInputImages[aImage.mInputIndex];
+
+      RefPtr<FilterNode> transform = mDT->CreateFilter(FilterType::TRANSFORM);
+      if (!transform) {
+        return nullptr;
+      }
+      transform->SetInput(IN_TRANSFORM_IN, inputImage);
+      transform->SetAttribute(ATT_TRANSFORM_MATRIX, TM);
+      transform->SetAttribute(ATT_TRANSFORM_FILTER, aImage.mFilter);
+      return transform.forget();
+    }
+
+    already_AddRefed<FilterNode> operator()(const ToAlphaAttributes& aToAlpha) {
+      return FilterWrappers::ToAlpha(mDT, mSources[0]);
+    }
+  };
+
+  return aDescription.Attributes().match(PrimitiveAttributesMatcher(
+      aDescription, aDT, aSources, aSourceRegions, aInputImages));
+}
+
+template <typename T>
+static const T& ElementForIndex(int32_t aIndex,
+                                const nsTArray<T>& aPrimitiveElements,
+                                const T& aSourceGraphicElement,
+                                const T& aFillPaintElement,
+                                const T& aStrokePaintElement) {
+  switch (aIndex) {
+    case FilterPrimitiveDescription::kPrimitiveIndexSourceGraphic:
+    case FilterPrimitiveDescription::kPrimitiveIndexSourceAlpha:
+      return aSourceGraphicElement;
+    case FilterPrimitiveDescription::kPrimitiveIndexFillPaint:
+      return aFillPaintElement;
+    case FilterPrimitiveDescription::kPrimitiveIndexStrokePaint:
+      return aStrokePaintElement;
+    default:
+      MOZ_ASSERT(aIndex >= 0, "bad index");
+      return aPrimitiveElements[aIndex];
+  }
+}
+
+static AlphaModel InputAlphaModelForPrimitive(
+    const FilterPrimitiveDescription& aDescr, int32_t aInputIndex,
+    AlphaModel aOriginalAlphaModel) {
+  const PrimitiveAttributes& atts = aDescr.Attributes();
+  if (atts.is<TileAttributes>() || atts.is<OffsetAttributes>() ||
+      atts.is<ToAlphaAttributes>()) {
+    return aOriginalAlphaModel;
+  }
+  if (atts.is<ColorMatrixAttributes>() ||
+      atts.is<ComponentTransferAttributes>()) {
+    return AlphaModel::Unpremultiplied;
+  }
+  if (atts.is<DisplacementMapAttributes>()) {
+    return aInputIndex == 0 ? AlphaModel::Premultiplied
+                            : AlphaModel::Unpremultiplied;
+  }
+  if (atts.is<ConvolveMatrixAttributes>()) {
+    return atts.as<ConvolveMatrixAttributes>().mPreserveAlpha
+               ? AlphaModel::Unpremultiplied
+               : AlphaModel::Premultiplied;
+  }
+  return AlphaModel::Premultiplied;
+}
+
+static AlphaModel OutputAlphaModelForPrimitive(
+    const FilterPrimitiveDescription& aDescr,
+    const nsTArray<AlphaModel>& aInputAlphaModels) {
+  if (aInputAlphaModels.Length()) {
+    // For filters with inputs, the output is premultiplied if and only if the
+    // first input is premultiplied.
+    return InputAlphaModelForPrimitive(aDescr, 0, aInputAlphaModels[0]);
+  }
+
+  // All filters without inputs produce premultiplied alpha.
+  return AlphaModel::Premultiplied;
+}
+
+// Returns the output FilterNode, in premultiplied sRGB space.
+already_AddRefed<FilterNode> FilterNodeGraphFromDescription(
+    DrawTarget* aDT, const FilterDescription& aFilter,
+    const Rect& aResultNeededRect, FilterNode* aSourceGraphic,
+    const IntRect& aSourceGraphicRect, FilterNode* aFillPaint,
+    FilterNode* aStrokePaint,
+    nsTArray<RefPtr<SourceSurface>>& aAdditionalImages) {
+  const nsTArray<FilterPrimitiveDescription>& primitives = aFilter.mPrimitives;
+  MOZ_RELEASE_ASSERT(!primitives.IsEmpty());
+
+  RefPtr<FilterCachedColorModels> sourceFilters[4];
+  nsTArray<RefPtr<FilterCachedColorModels>> primitiveFilters;
+
+  for (size_t i = 0; i < primitives.Length(); ++i) {
+    const FilterPrimitiveDescription& descr = primitives[i];
+
+    nsTArray<RefPtr<FilterNode>> inputFilterNodes;
+    nsTArray<IntRect> inputSourceRects;
+    nsTArray<AlphaModel> inputAlphaModels;
+
+    for (size_t j = 0; j < descr.NumberOfInputs(); j++) {
+      int32_t inputIndex = descr.InputPrimitiveIndex(j);
+      if (inputIndex < 0) {
+        inputSourceRects.AppendElement(descr.FilterSpaceBounds());
+      } else {
+        inputSourceRects.AppendElement(
+            primitives[inputIndex].PrimitiveSubregion());
+      }
+
+      RefPtr<FilterCachedColorModels> inputFilter;
+      if (inputIndex >= 0) {
+        MOZ_ASSERT(inputIndex < (int64_t)primitiveFilters.Length(),
+                   "out-of-bounds input index!");
+        inputFilter = primitiveFilters[inputIndex];
+        MOZ_ASSERT(
+            inputFilter,
+            "Referred to input filter that comes after the current one?");
+      } else {
+        int32_t sourceIndex = -inputIndex - 1;
+        MOZ_ASSERT(sourceIndex >= 0, "invalid source index");
+        MOZ_ASSERT(sourceIndex < 4, "invalid source index");
+        inputFilter = sourceFilters[sourceIndex];
+        if (!inputFilter) {
+          RefPtr<FilterNode> sourceFilterNode;
+
+          nsTArray<FilterNode*> primitiveFilters;
+          RefPtr<FilterNode> filt =
+              ElementForIndex(inputIndex, primitiveFilters, aSourceGraphic,
+                              aFillPaint, aStrokePaint);
+          if (filt) {
+            sourceFilterNode = filt;
+
+            // Clip the original SourceGraphic to the first filter region if the
+            // surface isn't already sized appropriately.
+            if ((inputIndex ==
+                     FilterPrimitiveDescription::kPrimitiveIndexSourceGraphic ||
+                 inputIndex ==
+                     FilterPrimitiveDescription::kPrimitiveIndexSourceAlpha) &&
+                !descr.FilterSpaceBounds().Contains(aSourceGraphicRect)) {
+              sourceFilterNode = FilterWrappers::Crop(
+                  aDT, sourceFilterNode, descr.FilterSpaceBounds());
+            }
+
+            if (inputIndex ==
+                FilterPrimitiveDescription::kPrimitiveIndexSourceAlpha) {
+              sourceFilterNode = FilterWrappers::ToAlpha(aDT, sourceFilterNode);
+            }
+          }
+
+          inputFilter = new FilterCachedColorModels(aDT, sourceFilterNode,
+                                                    ColorModel::PremulSRGB());
+          sourceFilters[sourceIndex] = inputFilter;
+        }
+      }
+      MOZ_ASSERT(inputFilter);
+
+      AlphaModel inputAlphaModel = InputAlphaModelForPrimitive(
+          descr, j, inputFilter->OriginalAlphaModel());
+      inputAlphaModels.AppendElement(inputAlphaModel);
+      ColorModel inputColorModel(descr.InputColorSpace(j), inputAlphaModel);
+      inputFilterNodes.AppendElement(
+          inputFilter->ForColorModel(inputColorModel));
+    }
+
+    RefPtr<FilterNode> primitiveFilterNode = FilterNodeFromPrimitiveDescription(
+        descr, aDT, inputFilterNodes, inputSourceRects, aAdditionalImages);
+
+    if (primitiveFilterNode) {
+      primitiveFilterNode = FilterWrappers::Crop(aDT, primitiveFilterNode,
+                                                 descr.PrimitiveSubregion());
+    }
+
+    ColorModel outputColorModel(
+        descr.OutputColorSpace(),
+        OutputAlphaModelForPrimitive(descr, inputAlphaModels));
+    RefPtr<FilterCachedColorModels> primitiveFilter =
+        new FilterCachedColorModels(aDT, primitiveFilterNode, outputColorModel);
+
+    primitiveFilters.AppendElement(primitiveFilter);
+  }
+
+  MOZ_RELEASE_ASSERT(!primitiveFilters.IsEmpty());
+  return primitiveFilters.LastElement()->ForColorModel(
+      ColorModel::PremulSRGB());
+}
+
+// FilterSupport
+
+void FilterSupport::RenderFilterDescription(
+    DrawTarget* aDT, const FilterDescription& aFilter, const Rect& aRenderRect,
+    SourceSurface* aSourceGraphic, const IntRect& aSourceGraphicRect,
+    SourceSurface* aFillPaint, const IntRect& aFillPaintRect,
+    SourceSurface* aStrokePaint, const IntRect& aStrokePaintRect,
+    nsTArray<RefPtr<SourceSurface>>& aAdditionalImages, const Point& aDestPoint,
+    const DrawOptions& aOptions) {
+  RefPtr<FilterNode> sourceGraphic, fillPaint, strokePaint;
+  if (aSourceGraphic) {
+    sourceGraphic = FilterWrappers::ForSurface(aDT, aSourceGraphic,
+                                               aSourceGraphicRect.TopLeft());
+  }
+  if (aFillPaint) {
+    fillPaint =
+        FilterWrappers::ForSurface(aDT, aFillPaint, aFillPaintRect.TopLeft());
+  }
+  if (aStrokePaint) {
+    strokePaint = FilterWrappers::ForSurface(aDT, aStrokePaint,
+                                             aStrokePaintRect.TopLeft());
+  }
+  RefPtr<FilterNode> resultFilter = FilterNodeGraphFromDescription(
+      aDT, aFilter, aRenderRect, sourceGraphic, aSourceGraphicRect, fillPaint,
+      strokePaint, aAdditionalImages);
+  if (!resultFilter) {
+    gfxWarning() << "Filter is NULL.";
+    return;
+  }
+  aDT->DrawFilter(resultFilter, aRenderRect, aDestPoint, aOptions);
+}
+
+static nsIntRegion UnionOfRegions(const nsTArray<nsIntRegion>& aRegions) {
+  nsIntRegion result;
+  for (size_t i = 0; i < aRegions.Length(); i++) {
+    result.Or(result, aRegions[i]);
+  }
+  return result;
+}
+
+static int32_t InflateSizeForBlurStdDev(float aStdDev) {
+  double size =
+      std::min(aStdDev, kMaxStdDeviation) * (3 * sqrt(2 * M_PI) / 4) * 1.5;
+  return uint32_t(floor(size + 0.5));
+}
+
+static nsIntRegion ResultChangeRegionForPrimitive(
+    const FilterPrimitiveDescription& aDescription,
+    const nsTArray<nsIntRegion>& aInputChangeRegions) {
+  struct PrimitiveAttributesMatcher {
+    PrimitiveAttributesMatcher(const FilterPrimitiveDescription& aDescription,
+                               const nsTArray<nsIntRegion>& aInputChangeRegions)
+        : mDescription(aDescription),
+          mInputChangeRegions(aInputChangeRegions) {}
+
+    const FilterPrimitiveDescription& mDescription;
+    const nsTArray<nsIntRegion>& mInputChangeRegions;
+
+    nsIntRegion operator()(const EmptyAttributes& aEmptyAttributes) {
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const BlendAttributes& aBlend) {
+      return UnionOfRegions(mInputChangeRegions);
+    }
+
+    nsIntRegion operator()(const ColorMatrixAttributes& aColorMatrix) {
+      return mInputChangeRegions[0];
+    }
+
+    nsIntRegion operator()(const MorphologyAttributes& aMorphology) {
+      Size radii = aMorphology.mRadii;
+      int32_t rx = clamped(int32_t(ceil(radii.width)), 0, kMorphologyMaxRadius);
+      int32_t ry =
+          clamped(int32_t(ceil(radii.height)), 0, kMorphologyMaxRadius);
+      return mInputChangeRegions[0].Inflated(nsIntMargin(ry, rx, ry, rx));
+    }
+
+    nsIntRegion operator()(const FloodAttributes& aFlood) {
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const TileAttributes& aTile) {
+      return mDescription.PrimitiveSubregion();
+    }
+
+    nsIntRegion operator()(
+        const ComponentTransferAttributes& aComponentTransfer) {
+      return mInputChangeRegions[0];
+    }
+
+    nsIntRegion operator()(const OpacityAttributes& aOpacity) {
+      return UnionOfRegions(mInputChangeRegions);
+    }
+
+    nsIntRegion operator()(const ConvolveMatrixAttributes& aConvolveMatrix) {
+      if (aConvolveMatrix.mEdgeMode != EDGE_MODE_NONE) {
+        return mDescription.PrimitiveSubregion();
+      }
+      Size kernelUnitLength = aConvolveMatrix.mKernelUnitLength;
+      IntSize kernelSize = aConvolveMatrix.mKernelSize;
+      IntPoint target = aConvolveMatrix.mTarget;
+      nsIntMargin m(
+          ceil(kernelUnitLength.width * (target.x)),
+          ceil(kernelUnitLength.height * (target.y)),
+          ceil(kernelUnitLength.width * (kernelSize.width - target.x - 1)),
+          ceil(kernelUnitLength.height * (kernelSize.height - target.y - 1)));
+      return mInputChangeRegions[0].Inflated(m);
+    }
+
+    nsIntRegion operator()(const OffsetAttributes& aOffset) {
+      IntPoint offset = aOffset.mValue;
+      return mInputChangeRegions[0].MovedBy(offset.x, offset.y);
+    }
+
+    nsIntRegion operator()(const DisplacementMapAttributes& aDisplacementMap) {
+      int32_t scale = ceil(std::abs(aDisplacementMap.mScale));
+      return mInputChangeRegions[0].Inflated(
+          nsIntMargin(scale, scale, scale, scale));
+    }
+
+    nsIntRegion operator()(const TurbulenceAttributes& aTurbulence) {
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const CompositeAttributes& aComposite) {
+      return UnionOfRegions(mInputChangeRegions);
+    }
+
+    nsIntRegion operator()(const MergeAttributes& aMerge) {
+      return UnionOfRegions(mInputChangeRegions);
+    }
+
+    nsIntRegion operator()(const GaussianBlurAttributes& aGaussianBlur) {
+      const Size& stdDeviation = aGaussianBlur.mStdDeviation;
+      int32_t dx = InflateSizeForBlurStdDev(stdDeviation.width);
+      int32_t dy = InflateSizeForBlurStdDev(stdDeviation.height);
+      return mInputChangeRegions[0].Inflated(nsIntMargin(dy, dx, dy, dx));
+    }
+
+    nsIntRegion operator()(const DropShadowAttributes& aDropShadow) {
+      IntPoint offset = IntPoint::Truncate(aDropShadow.mOffset);
+      nsIntRegion offsetRegion =
+          mInputChangeRegions[0].MovedBy(offset.x, offset.y);
+      Size stdDeviation = aDropShadow.mStdDeviation;
+      int32_t dx = InflateSizeForBlurStdDev(stdDeviation.width);
+      int32_t dy = InflateSizeForBlurStdDev(stdDeviation.height);
+      nsIntRegion blurRegion =
+          offsetRegion.Inflated(nsIntMargin(dy, dx, dy, dx));
+      blurRegion.Or(blurRegion, mInputChangeRegions[0]);
+      return blurRegion;
+    }
+
+    nsIntRegion operator()(const SpecularLightingAttributes& aLighting) {
+      return operator()(
+          *(static_cast<const DiffuseLightingAttributes*>(&aLighting)));
+    }
+
+    nsIntRegion operator()(const DiffuseLightingAttributes& aLighting) {
+      Size kernelUnitLength = aLighting.mKernelUnitLength;
+      int32_t dx = ceil(kernelUnitLength.width);
+      int32_t dy = ceil(kernelUnitLength.height);
+      return mInputChangeRegions[0].Inflated(nsIntMargin(dy, dx, dy, dx));
+    }
+
+    nsIntRegion operator()(const ImageAttributes& aImage) {
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const ToAlphaAttributes& aToAlpha) {
+      return mInputChangeRegions[0];
+    }
+  };
+
+  return aDescription.Attributes().match(
+      PrimitiveAttributesMatcher(aDescription, aInputChangeRegions));
+}
+
+/* static */
+nsIntRegion FilterSupport::ComputeResultChangeRegion(
+    const FilterDescription& aFilter, const nsIntRegion& aSourceGraphicChange,
+    const nsIntRegion& aFillPaintChange,
+    const nsIntRegion& aStrokePaintChange) {
+  const nsTArray<FilterPrimitiveDescription>& primitives = aFilter.mPrimitives;
+  MOZ_RELEASE_ASSERT(!primitives.IsEmpty());
+
+  nsTArray<nsIntRegion> resultChangeRegions;
+
+  for (int32_t i = 0; i < int32_t(primitives.Length()); ++i) {
+    const FilterPrimitiveDescription& descr = primitives[i];
+
+    nsTArray<nsIntRegion> inputChangeRegions;
+    for (size_t j = 0; j < descr.NumberOfInputs(); j++) {
+      int32_t inputIndex = descr.InputPrimitiveIndex(j);
+      MOZ_ASSERT(inputIndex < i, "bad input index");
+      nsIntRegion inputChangeRegion =
+          ElementForIndex(inputIndex, resultChangeRegions, aSourceGraphicChange,
+                          aFillPaintChange, aStrokePaintChange);
+      inputChangeRegions.AppendElement(inputChangeRegion);
+    }
+    nsIntRegion changeRegion =
+        ResultChangeRegionForPrimitive(descr, inputChangeRegions);
+    changeRegion.And(changeRegion, descr.PrimitiveSubregion());
+    resultChangeRegions.AppendElement(changeRegion);
+  }
+
+  MOZ_RELEASE_ASSERT(!resultChangeRegions.IsEmpty());
+  return resultChangeRegions[resultChangeRegions.Length() - 1];
+}
+
+static float ResultOfZeroUnderTransferFunction(
+    const ComponentTransferAttributes& aFunctionAttributes, int32_t channel) {
+  switch (aFunctionAttributes.mTypes[channel]) {
+    case SVG_FECOMPONENTTRANSFER_TYPE_TABLE: {
+      const nsTArray<float>& tableValues = aFunctionAttributes.mValues[channel];
+      if (tableValues.Length() < 2) {
+        return 0.0f;
+      }
+      return tableValues[0];
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_DISCRETE: {
+      const nsTArray<float>& tableValues = aFunctionAttributes.mValues[channel];
+      if (tableValues.Length() < 1) {
+        return 0.0f;
+      }
+      return tableValues[0];
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_LINEAR: {
+      const nsTArray<float>& values = aFunctionAttributes.mValues[channel];
+      return values[kComponentTransferInterceptIndex];
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_GAMMA: {
+      const nsTArray<float>& values = aFunctionAttributes.mValues[channel];
+      return values[kComponentTransferOffsetIndex];
+    }
+
+    case SVG_FECOMPONENTTRANSFER_TYPE_IDENTITY:
+    default:
+      return 0.0f;
+  }
+}
+
+nsIntRegion FilterSupport::PostFilterExtentsForPrimitive(
+    const FilterPrimitiveDescription& aDescription,
+    const nsTArray<nsIntRegion>& aInputExtents) {
+  struct PrimitiveAttributesMatcher {
+    PrimitiveAttributesMatcher(const FilterPrimitiveDescription& aDescription,
+                               const nsTArray<nsIntRegion>& aInputExtents)
+        : mDescription(aDescription), mInputExtents(aInputExtents) {}
+
+    const FilterPrimitiveDescription& mDescription;
+    const nsTArray<nsIntRegion>& mInputExtents;
+
+    nsIntRegion operator()(const EmptyAttributes& aEmptyAttributes) {
+      return IntRect();
+    }
+
+    nsIntRegion operator()(const BlendAttributes& aBlend) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const ColorMatrixAttributes& aColorMatrix) {
+      if (aColorMatrix.mType == (uint32_t)SVG_FECOLORMATRIX_TYPE_MATRIX) {
+        const nsTArray<float>& values = aColorMatrix.mValues;
+        if (values.Length() == 20 && values[19] > 0.0f) {
+          return mDescription.PrimitiveSubregion();
+        }
+      }
+      return mInputExtents[0];
+    }
+
+    nsIntRegion operator()(const MorphologyAttributes& aMorphology) {
+      uint32_t op = aMorphology.mOperator;
+      if (op == SVG_OPERATOR_ERODE) {
+        return mInputExtents[0];
+      }
+      Size radii = aMorphology.mRadii;
+      int32_t rx = clamped(int32_t(ceil(radii.width)), 0, kMorphologyMaxRadius);
+      int32_t ry =
+          clamped(int32_t(ceil(radii.height)), 0, kMorphologyMaxRadius);
+      return mInputExtents[0].Inflated(nsIntMargin(ry, rx, ry, rx));
+    }
+
+    nsIntRegion operator()(const FloodAttributes& aFlood) {
+      if (aFlood.mColor.a == 0.0f) {
+        return IntRect();
+      }
+      return mDescription.PrimitiveSubregion();
+    }
+
+    nsIntRegion operator()(const TileAttributes& aTile) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(
+        const ComponentTransferAttributes& aComponentTransfer) {
+      if (ResultOfZeroUnderTransferFunction(aComponentTransfer, kChannelA) >
+          0.0f) {
+        return mDescription.PrimitiveSubregion();
+      }
+      return mInputExtents[0];
+    }
+
+    nsIntRegion operator()(const OpacityAttributes& aOpacity) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const ConvolveMatrixAttributes& aConvolveMatrix) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const OffsetAttributes& aOffset) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const DisplacementMapAttributes& aDisplacementMap) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const TurbulenceAttributes& aTurbulence) {
+      return mDescription.PrimitiveSubregion();
+    }
+
+    nsIntRegion operator()(const CompositeAttributes& aComposite) {
+      uint32_t op = aComposite.mOperator;
+      if (op == SVG_FECOMPOSITE_OPERATOR_ARITHMETIC) {
+        // The arithmetic composite primitive can draw outside the bounding
+        // box of its source images.
+        const nsTArray<float>& coefficients = aComposite.mCoefficients;
+        MOZ_ASSERT(coefficients.Length() == 4);
+
+        // The calculation is:
+        // r = c[0] * in[0] * in[1] + c[1] * in[0] + c[2] * in[1] + c[3]
+        nsIntRegion region;
+        if (coefficients[0] > 0.0f) {
+          region = mInputExtents[0].Intersect(mInputExtents[1]);
+        }
+        if (coefficients[1] > 0.0f) {
+          region.Or(region, mInputExtents[0]);
+        }
+        if (coefficients[2] > 0.0f) {
+          region.Or(region, mInputExtents[1]);
+        }
+        if (coefficients[3] > 0.0f) {
+          region = mDescription.PrimitiveSubregion();
+        }
+        return region;
+      }
+      if (op == SVG_FECOMPOSITE_OPERATOR_IN) {
+        return mInputExtents[0].Intersect(mInputExtents[1]);
+      }
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const MergeAttributes& aMerge) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const GaussianBlurAttributes& aGaussianBlur) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const DropShadowAttributes& aDropShadow) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+
+    nsIntRegion operator()(const DiffuseLightingAttributes& aDiffuseLighting) {
+      return mDescription.PrimitiveSubregion();
+    }
+
+    nsIntRegion operator()(
+        const SpecularLightingAttributes& aSpecularLighting) {
+      return mDescription.PrimitiveSubregion();
+    }
+
+    nsIntRegion operator()(const ImageAttributes& aImage) {
+      return mDescription.PrimitiveSubregion();
+    }
+
+    nsIntRegion operator()(const ToAlphaAttributes& aToAlpha) {
+      return ResultChangeRegionForPrimitive(mDescription, mInputExtents);
+    }
+  };
+
+  return aDescription.Attributes().match(
+      PrimitiveAttributesMatcher(aDescription, aInputExtents));
+}
+
+/* static */
+nsIntRegion FilterSupport::ComputePostFilterExtents(
+    const FilterDescription& aFilter,
+    const nsIntRegion& aSourceGraphicExtents) {
+  const nsTArray<FilterPrimitiveDescription>& primitives = aFilter.mPrimitives;
+  MOZ_RELEASE_ASSERT(!primitives.IsEmpty());
+  nsTArray<nsIntRegion> postFilterExtents;
+
+  for (int32_t i = 0; i < int32_t(primitives.Length()); ++i) {
+    const FilterPrimitiveDescription& descr = primitives[i];
+    nsIntRegion filterSpace = descr.FilterSpaceBounds();
+
+    nsTArray<nsIntRegion> inputExtents;
+    for (size_t j = 0; j < descr.NumberOfInputs(); j++) {
+      int32_t inputIndex = descr.InputPrimitiveIndex(j);
+      MOZ_ASSERT(inputIndex < i, "bad input index");
+      nsIntRegion inputExtent =
+          ElementForIndex(inputIndex, postFilterExtents, aSourceGraphicExtents,
+                          filterSpace, filterSpace);
+      inputExtents.AppendElement(inputExtent);
+    }
+    nsIntRegion extent = PostFilterExtentsForPrimitive(descr, inputExtents);
+    extent.And(extent, descr.PrimitiveSubregion());
+    postFilterExtents.AppendElement(extent);
+  }
+
+  MOZ_RELEASE_ASSERT(!postFilterExtents.IsEmpty());
+  return postFilterExtents[postFilterExtents.Length() - 1];
+}
+
+static nsIntRegion SourceNeededRegionForPrimitive(
+    const FilterPrimitiveDescription& aDescription,
+    const nsIntRegion& aResultNeededRegion, int32_t aInputIndex) {
+  struct PrimitiveAttributesMatcher {
+    PrimitiveAttributesMatcher(const FilterPrimitiveDescription& aDescription,
+                               const nsIntRegion& aResultNeededRegion,
+                               int32_t aInputIndex)
+        : mDescription(aDescription),
+          mResultNeededRegion(aResultNeededRegion),
+          mInputIndex(aInputIndex) {}
+
+    const FilterPrimitiveDescription& mDescription;
+    const nsIntRegion& mResultNeededRegion;
+    const int32_t mInputIndex;
+
+    nsIntRegion operator()(const EmptyAttributes& aEmptyAttributes) {
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const BlendAttributes& aBlend) {
+      return mResultNeededRegion;
+    }
+
+    nsIntRegion operator()(const ColorMatrixAttributes& aColorMatrix) {
+      return mResultNeededRegion;
+    }
+
+    nsIntRegion operator()(const MorphologyAttributes& aMorphology) {
+      Size radii = aMorphology.mRadii;
+      int32_t rx = clamped(int32_t(ceil(radii.width)), 0, kMorphologyMaxRadius);
+      int32_t ry =
+          clamped(int32_t(ceil(radii.height)), 0, kMorphologyMaxRadius);
+      return mResultNeededRegion.Inflated(nsIntMargin(ry, rx, ry, rx));
+    }
+
+    nsIntRegion operator()(const FloodAttributes& aFlood) {
+      MOZ_CRASH("GFX: this shouldn't be called for filters without inputs");
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const TileAttributes& aTile) {
+      return IntRect(INT32_MIN / 2, INT32_MIN / 2, INT32_MAX, INT32_MAX);
+    }
+
+    nsIntRegion operator()(
+        const ComponentTransferAttributes& aComponentTransfer) {
+      return mResultNeededRegion;
+    }
+
+    nsIntRegion operator()(const OpacityAttributes& aOpacity) {
+      return mResultNeededRegion;
+    }
+
+    nsIntRegion operator()(const ConvolveMatrixAttributes& aConvolveMatrix) {
+      Size kernelUnitLength = aConvolveMatrix.mKernelUnitLength;
+      IntSize kernelSize = aConvolveMatrix.mKernelSize;
+      IntPoint target = aConvolveMatrix.mTarget;
+      nsIntMargin m(
+          ceil(kernelUnitLength.width * (kernelSize.width - target.x - 1)),
+          ceil(kernelUnitLength.height * (kernelSize.height - target.y - 1)),
+          ceil(kernelUnitLength.width * (target.x)),
+          ceil(kernelUnitLength.height * (target.y)));
+      return mResultNeededRegion.Inflated(m);
+    }
+
+    nsIntRegion operator()(const OffsetAttributes& aOffset) {
+      IntPoint offset = aOffset.mValue;
+      return mResultNeededRegion.MovedBy(-nsIntPoint(offset.x, offset.y));
+    }
+
+    nsIntRegion operator()(const DisplacementMapAttributes& aDisplacementMap) {
+      if (mInputIndex == 1) {
+        return mResultNeededRegion;
+      }
+      int32_t scale = ceil(std::abs(aDisplacementMap.mScale));
+      return mResultNeededRegion.Inflated(
+          nsIntMargin(scale, scale, scale, scale));
+    }
+
+    nsIntRegion operator()(const TurbulenceAttributes& aTurbulence) {
+      MOZ_CRASH("GFX: this shouldn't be called for filters without inputs");
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const CompositeAttributes& aComposite) {
+      return mResultNeededRegion;
+    }
+
+    nsIntRegion operator()(const MergeAttributes& aMerge) {
+      return mResultNeededRegion;
+    }
+
+    nsIntRegion operator()(const GaussianBlurAttributes& aGaussianBlur) {
+      const Size& stdDeviation = aGaussianBlur.mStdDeviation;
+      int32_t dx = InflateSizeForBlurStdDev(stdDeviation.width);
+      int32_t dy = InflateSizeForBlurStdDev(stdDeviation.height);
+      return mResultNeededRegion.Inflated(nsIntMargin(dy, dx, dy, dx));
+    }
+
+    nsIntRegion operator()(const DropShadowAttributes& aDropShadow) {
+      IntPoint offset = IntPoint::Truncate(aDropShadow.mOffset);
+      nsIntRegion offsetRegion =
+          mResultNeededRegion.MovedBy(-nsIntPoint(offset.x, offset.y));
+      Size stdDeviation = aDropShadow.mStdDeviation;
+      int32_t dx = InflateSizeForBlurStdDev(stdDeviation.width);
+      int32_t dy = InflateSizeForBlurStdDev(stdDeviation.height);
+      nsIntRegion blurRegion =
+          offsetRegion.Inflated(nsIntMargin(dy, dx, dy, dx));
+      blurRegion.Or(blurRegion, mResultNeededRegion);
+      return blurRegion;
+    }
+
+    nsIntRegion operator()(const SpecularLightingAttributes& aLighting) {
+      return operator()(
+          *(static_cast<const DiffuseLightingAttributes*>(&aLighting)));
+    }
+
+    nsIntRegion operator()(const DiffuseLightingAttributes& aLighting) {
+      Size kernelUnitLength = aLighting.mKernelUnitLength;
+      int32_t dx = ceil(kernelUnitLength.width);
+      int32_t dy = ceil(kernelUnitLength.height);
+      return mResultNeededRegion.Inflated(nsIntMargin(dy, dx, dy, dx));
+    }
+
+    nsIntRegion operator()(const ImageAttributes& aImage) {
+      MOZ_CRASH("GFX: this shouldn't be called for filters without inputs");
+      return nsIntRegion();
+    }
+
+    nsIntRegion operator()(const ToAlphaAttributes& aToAlpha) {
+      return mResultNeededRegion;
+    }
+  };
+
+  return aDescription.Attributes().match(PrimitiveAttributesMatcher(
+      aDescription, aResultNeededRegion, aInputIndex));
+}
+
+/* static */
+void FilterSupport::ComputeSourceNeededRegions(
+    const FilterDescription& aFilter, const nsIntRegion& aResultNeededRegion,
+    nsIntRegion& aSourceGraphicNeededRegion,
+    nsIntRegion& aFillPaintNeededRegion,
+    nsIntRegion& aStrokePaintNeededRegion) {
+  const nsTArray<FilterPrimitiveDescription>& primitives = aFilter.mPrimitives;
+  MOZ_ASSERT(!primitives.IsEmpty());
+  if (primitives.IsEmpty()) {
+    return;
+  }
+
+  nsTArray<nsIntRegion> primitiveNeededRegions;
+  primitiveNeededRegions.AppendElements(primitives.Length());
+
+  primitiveNeededRegions[primitives.Length() - 1] = aResultNeededRegion;
+
+  for (int32_t i = primitives.Length() - 1; i >= 0; --i) {
+    const FilterPrimitiveDescription& descr = primitives[i];
+    nsIntRegion neededRegion = primitiveNeededRegions[i];
+    neededRegion.And(neededRegion, descr.PrimitiveSubregion());
+
+    for (size_t j = 0; j < descr.NumberOfInputs(); j++) {
+      int32_t inputIndex = descr.InputPrimitiveIndex(j);
+      MOZ_ASSERT(inputIndex < i, "bad input index");
+      nsIntRegion* inputNeededRegion =
+          const_cast<nsIntRegion*>(&ElementForIndex(
+              inputIndex, primitiveNeededRegions, aSourceGraphicNeededRegion,
+              aFillPaintNeededRegion, aStrokePaintNeededRegion));
+      inputNeededRegion->Or(*inputNeededRegion, SourceNeededRegionForPrimitive(
+                                                    descr, neededRegion, j));
+    }
+  }
+
+  // Clip original SourceGraphic to first filter region.
+  const FilterPrimitiveDescription& firstDescr = primitives[0];
+  aSourceGraphicNeededRegion.And(aSourceGraphicNeededRegion,
+                                 firstDescr.FilterSpaceBounds());
+}
+
+// FilterPrimitiveDescription
+
+FilterPrimitiveDescription::FilterPrimitiveDescription()
+    : mAttributes(EmptyAttributes()),
+      mOutputColorSpace(ColorSpace::SRGB),
+      mIsTainted(false) {}
+
+FilterPrimitiveDescription::FilterPrimitiveDescription(
+    PrimitiveAttributes&& aAttributes)
+    : mAttributes(std::move(aAttributes)),
+      mOutputColorSpace(ColorSpace::SRGB),
+      mIsTainted(false) {}
+
+bool FilterPrimitiveDescription::operator==(
+    const FilterPrimitiveDescription& aOther) const {
+  return mFilterPrimitiveSubregion.IsEqualInterior(
+             aOther.mFilterPrimitiveSubregion) &&
+         mFilterSpaceBounds.IsEqualInterior(aOther.mFilterSpaceBounds) &&
+         mOutputColorSpace == aOther.mOutputColorSpace &&
+         mIsTainted == aOther.mIsTainted &&
+         mInputPrimitives == aOther.mInputPrimitives &&
+         mInputColorSpaces == aOther.mInputColorSpaces &&
+         mAttributes == aOther.mAttributes;
+}
+
+// FilterDescription
+
+bool FilterDescription::operator==(const FilterDescription& aOther) const {
+  return mPrimitives == aOther.mPrimitives;
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/src/FilterSupport.h b/gfx/src/FilterSupport.h
new file mode 100644
index 0000000000..94c535ab0f
--- /dev/null
+++ b/gfx/src/FilterSupport.h
@@ -0,0 +1,466 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __FilterSupport_h
+#define __FilterSupport_h
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Matrix.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/Rect.h"
+#include "nsRegion.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+namespace gfx {
+class FilterPrimitiveDescription;
+class FilterNode;
+struct FilterDescription;
+}  // namespace gfx
+}  // namespace mozilla
+
+extern const float gsRGBToLinearRGBMap[256];
+
+namespace mozilla {
+namespace gfx {
+namespace FilterWrappers {
+extern already_AddRefed<FilterNode> Clear(DrawTarget* aDT);
+extern already_AddRefed<FilterNode> ForSurface(
+    DrawTarget* aDT, SourceSurface* aSurface, const IntPoint& aSurfacePosition);
+}  // namespace FilterWrappers
+
+// Morphology Operators
+const unsigned short SVG_OPERATOR_UNKNOWN = 0;
+const unsigned short SVG_OPERATOR_ERODE = 1;
+const unsigned short SVG_OPERATOR_DILATE = 2;
+
+// ColorMatrix types
+const unsigned short SVG_FECOLORMATRIX_TYPE_UNKNOWN = 0;
+const unsigned short SVG_FECOLORMATRIX_TYPE_MATRIX = 1;
+const unsigned short SVG_FECOLORMATRIX_TYPE_SATURATE = 2;
+const unsigned short SVG_FECOLORMATRIX_TYPE_HUE_ROTATE = 3;
+const unsigned short SVG_FECOLORMATRIX_TYPE_LUMINANCE_TO_ALPHA = 4;
+// ColorMatrix types for CSS filters
+const unsigned short SVG_FECOLORMATRIX_TYPE_SEPIA = 5;
+
+// ComponentTransfer types
+const unsigned short SVG_FECOMPONENTTRANSFER_TYPE_UNKNOWN = 0;
+const unsigned short SVG_FECOMPONENTTRANSFER_TYPE_IDENTITY = 1;
+const unsigned short SVG_FECOMPONENTTRANSFER_TYPE_TABLE = 2;
+const unsigned short SVG_FECOMPONENTTRANSFER_TYPE_DISCRETE = 3;
+const unsigned short SVG_FECOMPONENTTRANSFER_TYPE_LINEAR = 4;
+const unsigned short SVG_FECOMPONENTTRANSFER_TYPE_GAMMA = 5;
+const unsigned short SVG_FECOMPONENTTRANSFER_SAME_AS_R = 6;
+
+// Blend Mode Values
+const unsigned short SVG_FEBLEND_MODE_UNKNOWN = 0;
+const unsigned short SVG_FEBLEND_MODE_NORMAL = 1;
+const unsigned short SVG_FEBLEND_MODE_MULTIPLY = 2;
+const unsigned short SVG_FEBLEND_MODE_SCREEN = 3;
+const unsigned short SVG_FEBLEND_MODE_DARKEN = 4;
+const unsigned short SVG_FEBLEND_MODE_LIGHTEN = 5;
+const unsigned short SVG_FEBLEND_MODE_OVERLAY = 6;
+const unsigned short SVG_FEBLEND_MODE_COLOR_DODGE = 7;
+const unsigned short SVG_FEBLEND_MODE_COLOR_BURN = 8;
+const unsigned short SVG_FEBLEND_MODE_HARD_LIGHT = 9;
+const unsigned short SVG_FEBLEND_MODE_SOFT_LIGHT = 10;
+const unsigned short SVG_FEBLEND_MODE_DIFFERENCE = 11;
+const unsigned short SVG_FEBLEND_MODE_EXCLUSION = 12;
+const unsigned short SVG_FEBLEND_MODE_HUE = 13;
+const unsigned short SVG_FEBLEND_MODE_SATURATION = 14;
+const unsigned short SVG_FEBLEND_MODE_COLOR = 15;
+const unsigned short SVG_FEBLEND_MODE_LUMINOSITY = 16;
+
+// Edge Mode Values
+const unsigned short SVG_EDGEMODE_UNKNOWN = 0;
+const unsigned short SVG_EDGEMODE_DUPLICATE = 1;
+const unsigned short SVG_EDGEMODE_WRAP = 2;
+const unsigned short SVG_EDGEMODE_NONE = 3;
+
+// Channel Selectors
+const unsigned short SVG_CHANNEL_UNKNOWN = 0;
+const unsigned short SVG_CHANNEL_R = 1;
+const unsigned short SVG_CHANNEL_G = 2;
+const unsigned short SVG_CHANNEL_B = 3;
+const unsigned short SVG_CHANNEL_A = 4;
+
+// Turbulence Types
+const unsigned short SVG_TURBULENCE_TYPE_UNKNOWN = 0;
+const unsigned short SVG_TURBULENCE_TYPE_FRACTALNOISE = 1;
+const unsigned short SVG_TURBULENCE_TYPE_TURBULENCE = 2;
+
+// Composite Operators
+const unsigned short SVG_FECOMPOSITE_OPERATOR_UNKNOWN = 0;
+const unsigned short SVG_FECOMPOSITE_OPERATOR_OVER = 1;
+const unsigned short SVG_FECOMPOSITE_OPERATOR_IN = 2;
+const unsigned short SVG_FECOMPOSITE_OPERATOR_OUT = 3;
+const unsigned short SVG_FECOMPOSITE_OPERATOR_ATOP = 4;
+const unsigned short SVG_FECOMPOSITE_OPERATOR_XOR = 5;
+const unsigned short SVG_FECOMPOSITE_OPERATOR_ARITHMETIC = 6;
+const unsigned short SVG_FECOMPOSITE_OPERATOR_LIGHTER = 7;
+
+struct FilterAttribute;
+
+// Limits
+const float kMaxStdDeviation = 500;
+
+// Simple PrimitiveAttributes:
+
+struct EmptyAttributes {
+  bool operator==(const EmptyAttributes& aOther) const { return true; }
+};
+
+struct BlendAttributes {
+  uint32_t mBlendMode;
+
+  bool operator==(const BlendAttributes& aOther) const {
+    return mBlendMode == aOther.mBlendMode;
+  }
+};
+
+struct MorphologyAttributes {
+  uint32_t mOperator;
+  Size mRadii;
+
+  bool operator==(const MorphologyAttributes& aOther) const {
+    return mOperator == aOther.mOperator && mRadii == aOther.mRadii;
+  }
+};
+
+struct FloodAttributes {
+  sRGBColor mColor;
+
+  bool operator==(const FloodAttributes& aOther) const {
+    return mColor == aOther.mColor;
+  }
+};
+
+struct TileAttributes {
+  bool operator==(const TileAttributes& aOther) const { return true; }
+};
+
+struct OpacityAttributes {
+  float mOpacity;
+
+  bool operator==(const OpacityAttributes& aOther) const {
+    return mOpacity == aOther.mOpacity;
+  }
+};
+
+struct OffsetAttributes {
+  IntPoint mValue;
+
+  bool operator==(const OffsetAttributes& aOther) const {
+    return mValue == aOther.mValue;
+  }
+};
+
+struct DisplacementMapAttributes {
+  float mScale;
+  uint32_t mXChannel;
+  uint32_t mYChannel;
+
+  bool operator==(const DisplacementMapAttributes& aOther) const {
+    return mScale == aOther.mScale && mXChannel == aOther.mXChannel &&
+           mYChannel == aOther.mYChannel;
+  }
+};
+
+struct TurbulenceAttributes {
+  IntPoint mOffset;
+  Size mBaseFrequency;
+  float mSeed;
+  uint32_t mOctaves;
+  bool mStitchable;
+  uint32_t mType;
+
+  bool operator==(const TurbulenceAttributes& aOther) const {
+    return mOffset == aOther.mOffset &&
+           mBaseFrequency == aOther.mBaseFrequency && mSeed == aOther.mSeed &&
+           mOctaves == aOther.mOctaves && mStitchable == aOther.mStitchable &&
+           mType == aOther.mType;
+  }
+};
+
+struct MergeAttributes {
+  bool operator==(const MergeAttributes& aOther) const { return true; }
+};
+
+struct ImageAttributes {
+  uint32_t mFilter;
+  uint32_t mInputIndex;
+  Matrix mTransform;
+
+  bool operator==(const ImageAttributes& aOther) const {
+    return mFilter == aOther.mFilter && mInputIndex == aOther.mInputIndex &&
+           mTransform.ExactlyEquals(aOther.mTransform);
+  }
+};
+
+struct GaussianBlurAttributes {
+  Size mStdDeviation;
+
+  bool operator==(const GaussianBlurAttributes& aOther) const {
+    return mStdDeviation == aOther.mStdDeviation;
+  }
+};
+
+struct DropShadowAttributes {
+  Size mStdDeviation;
+  Point mOffset;
+  sRGBColor mColor;
+
+  bool operator==(const DropShadowAttributes& aOther) const {
+    return mStdDeviation == aOther.mStdDeviation && mOffset == aOther.mOffset &&
+           mColor == aOther.mColor;
+  }
+};
+
+struct ToAlphaAttributes {
+  bool operator==(const ToAlphaAttributes& aOther) const { return true; }
+};
+
+// Complex PrimitiveAttributes:
+
+class ImplicitlyCopyableFloatArray : public CopyableTArray<float> {
+ public:
+  ImplicitlyCopyableFloatArray() = default;
+
+  ImplicitlyCopyableFloatArray(ImplicitlyCopyableFloatArray&& aOther) = default;
+
+  ImplicitlyCopyableFloatArray& operator=(
+      ImplicitlyCopyableFloatArray&& aOther) = default;
+
+  ImplicitlyCopyableFloatArray(const ImplicitlyCopyableFloatArray& aOther) =
+      default;
+
+  ImplicitlyCopyableFloatArray& operator=(
+      const ImplicitlyCopyableFloatArray& aOther) = default;
+};
+
+struct ColorMatrixAttributes {
+  uint32_t mType;
+  ImplicitlyCopyableFloatArray mValues;
+
+  bool operator==(const ColorMatrixAttributes& aOther) const {
+    return mType == aOther.mType && mValues == aOther.mValues;
+  }
+};
+
+// If the types for G and B are SVG_FECOMPONENTTRANSFER_SAME_AS_R,
+// use the R channel values - this lets us avoid copies.
+const uint32_t kChannelROrRGB = 0;
+const uint32_t kChannelG = 1;
+const uint32_t kChannelB = 2;
+const uint32_t kChannelA = 3;
+
+const uint32_t kComponentTransferSlopeIndex = 0;
+const uint32_t kComponentTransferInterceptIndex = 1;
+
+const uint32_t kComponentTransferAmplitudeIndex = 0;
+const uint32_t kComponentTransferExponentIndex = 1;
+const uint32_t kComponentTransferOffsetIndex = 2;
+
+struct ComponentTransferAttributes {
+  uint8_t mTypes[4];
+  ImplicitlyCopyableFloatArray mValues[4];
+
+  bool operator==(const ComponentTransferAttributes& aOther) const {
+    return mTypes[0] == aOther.mTypes[0] && mTypes[1] == aOther.mTypes[1] &&
+           mTypes[2] == aOther.mTypes[2] && mTypes[3] == aOther.mTypes[3] &&
+           mValues[0] == aOther.mValues[0] && mValues[1] == aOther.mValues[1] &&
+           mValues[2] == aOther.mValues[2] && mValues[3] == aOther.mValues[3];
+  }
+};
+
+struct ConvolveMatrixAttributes {
+  IntSize mKernelSize;
+  ImplicitlyCopyableFloatArray mKernelMatrix;
+  float mDivisor;
+  float mBias;
+  IntPoint mTarget;
+  uint32_t mEdgeMode;
+  Size mKernelUnitLength;
+  bool mPreserveAlpha;
+
+  bool operator==(const ConvolveMatrixAttributes& aOther) const {
+    return mKernelSize == aOther.mKernelSize &&
+           mKernelMatrix == aOther.mKernelMatrix &&
+           mDivisor == aOther.mDivisor && mBias == aOther.mBias &&
+           mTarget == aOther.mTarget && mEdgeMode == aOther.mEdgeMode &&
+           mKernelUnitLength == aOther.mKernelUnitLength &&
+           mPreserveAlpha == aOther.mPreserveAlpha;
+  }
+};
+
+struct CompositeAttributes {
+  uint32_t mOperator;
+  ImplicitlyCopyableFloatArray mCoefficients;
+
+  bool operator==(const CompositeAttributes& aOther) const {
+    return mOperator == aOther.mOperator &&
+           mCoefficients == aOther.mCoefficients;
+  }
+};
+
+enum class LightType {
+  None = 0,
+  Point,
+  Spot,
+  Distant,
+  Max,
+};
+
+const uint32_t kDistantLightAzimuthIndex = 0;
+const uint32_t kDistantLightElevationIndex = 1;
+const uint32_t kDistantLightNumAttributes = 2;
+
+const uint32_t kPointLightPositionXIndex = 0;
+const uint32_t kPointLightPositionYIndex = 1;
+const uint32_t kPointLightPositionZIndex = 2;
+const uint32_t kPointLightNumAttributes = 3;
+
+const uint32_t kSpotLightPositionXIndex = 0;
+const uint32_t kSpotLightPositionYIndex = 1;
+const uint32_t kSpotLightPositionZIndex = 2;
+const uint32_t kSpotLightPointsAtXIndex = 3;
+const uint32_t kSpotLightPointsAtYIndex = 4;
+const uint32_t kSpotLightPointsAtZIndex = 5;
+const uint32_t kSpotLightFocusIndex = 6;
+const uint32_t kSpotLightLimitingConeAngleIndex = 7;
+const uint32_t kSpotLightNumAttributes = 8;
+
+struct DiffuseLightingAttributes {
+  LightType mLightType;
+  ImplicitlyCopyableFloatArray mLightValues;
+  float mSurfaceScale;
+  Size mKernelUnitLength;
+  sRGBColor mColor;
+  float mLightingConstant;
+  float mSpecularExponent;
+
+  bool operator==(const DiffuseLightingAttributes& aOther) const {
+    return mLightType == aOther.mLightType &&
+           mLightValues == aOther.mLightValues &&
+           mSurfaceScale == aOther.mSurfaceScale &&
+           mKernelUnitLength == aOther.mKernelUnitLength &&
+           mColor == aOther.mColor;
+  }
+};
+
+struct SpecularLightingAttributes : public DiffuseLightingAttributes {};
+
+enum class ColorSpace { SRGB, LinearRGB, Max };
+
+enum class AlphaModel { Unpremultiplied, Premultiplied };
+
+class ColorModel {
+ public:
+  static ColorModel PremulSRGB() {
+    return ColorModel(ColorSpace::SRGB, AlphaModel::Premultiplied);
+  }
+
+  ColorModel(ColorSpace aColorSpace, AlphaModel aAlphaModel)
+      : mColorSpace(aColorSpace), mAlphaModel(aAlphaModel) {}
+  ColorModel()
+      : mColorSpace(ColorSpace::SRGB), mAlphaModel(AlphaModel::Premultiplied) {}
+  bool operator==(const ColorModel& aOther) const {
+    return mColorSpace == aOther.mColorSpace &&
+           mAlphaModel == aOther.mAlphaModel;
+  }
+
+  // Used to index FilterCachedColorModels::mFilterForColorModel.
+  uint8_t ToIndex() const {
+    return static_cast<uint8_t>(static_cast<uint8_t>(mColorSpace) << 1) |
+           static_cast<uint8_t>(mAlphaModel);
+  }
+
+  ColorSpace mColorSpace;
+  AlphaModel mAlphaModel;
+};
+
+already_AddRefed<FilterNode> FilterNodeGraphFromDescription(
+    DrawTarget* aDT, const FilterDescription& aFilter,
+    const Rect& aResultNeededRect, FilterNode* aSourceGraphic,
+    const IntRect& aSourceGraphicRect, FilterNode* aFillPaint,
+    FilterNode* aStrokePaint,
+    nsTArray<RefPtr<SourceSurface>>& aAdditionalImages);
+
+/**
+ * The methods of this class are not on FilterDescription because
+ * FilterDescription is designed as a simple value holder that can be used
+ * on any thread.
+ */
+class FilterSupport {
+ public:
+  /**
+   * Draw the filter described by aFilter. All rect parameters are in filter
+   * space coordinates. aRenderRect specifies the part of the filter output
+   * that will be drawn at (0, 0) into the draw target aDT, subject to the
+   * current transform on aDT but with no additional scaling.
+   * The source surfaces must match their corresponding rect in size.
+   * aAdditionalImages carries the images that are referenced by the
+   * eImageInputIndex attribute on any image primitives in the filter.
+   */
+  static void RenderFilterDescription(
+      DrawTarget* aDT, const FilterDescription& aFilter,
+      const Rect& aRenderRect, SourceSurface* aSourceGraphic,
+      const IntRect& aSourceGraphicRect, SourceSurface* aFillPaint,
+      const IntRect& aFillPaintRect, SourceSurface* aStrokePaint,
+      const IntRect& aStrokePaintRect,
+      nsTArray<RefPtr<SourceSurface>>& aAdditionalImages,
+      const Point& aDestPoint, const DrawOptions& aOptions = DrawOptions());
+
+  /**
+   * Computes the region that changes in the filter output due to a change in
+   * input.  This is primarily needed when an individual piece of content inside
+   * a filtered container element changes.
+   */
+  static nsIntRegion ComputeResultChangeRegion(
+      const FilterDescription& aFilter, const nsIntRegion& aSourceGraphicChange,
+      const nsIntRegion& aFillPaintChange,
+      const nsIntRegion& aStrokePaintChange);
+
+  /**
+   * Computes the regions that need to be supplied in the filter inputs when
+   * painting aResultNeededRegion of the filter output.
+   */
+  static void ComputeSourceNeededRegions(
+      const FilterDescription& aFilter, const nsIntRegion& aResultNeededRegion,
+      nsIntRegion& aSourceGraphicNeededRegion,
+      nsIntRegion& aFillPaintNeededRegion,
+      nsIntRegion& aStrokePaintNeededRegion);
+
+  /**
+   * Computes the size of the filter output.
+   */
+  static nsIntRegion ComputePostFilterExtents(
+      const FilterDescription& aFilter,
+      const nsIntRegion& aSourceGraphicExtents);
+
+  /**
+   * Computes the size of a single FilterPrimitiveDescription's output given a
+   * set of input extents.
+   */
+  static nsIntRegion PostFilterExtentsForPrimitive(
+      const FilterPrimitiveDescription& aDescription,
+      const nsTArray<nsIntRegion>& aInputExtents);
+};
+
+/**
+ * Create a 4x5 color matrix for the different ways to specify color matrices
+ * in SVG.
+ *
+ * Return false if the input is invalid or if the resulting matrix is the
+ * identity.
+ */
+bool ComputeColorMatrix(const ColorMatrixAttributes& aMatrixAttributes,
+                        float aOutMatrix[20]);
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // __FilterSupport_h
diff --git a/gfx/src/FontPropertyTypes.h b/gfx/src/FontPropertyTypes.h
new file mode 100644
index 0000000000..fe4f1f06e4
--- /dev/null
+++ b/gfx/src/FontPropertyTypes.h
@@ -0,0 +1,167 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* font specific types shared by both thebes and layout */
+
+#ifndef GFX_FONT_PROPERTY_TYPES_H
+#define GFX_FONT_PROPERTY_TYPES_H
+
+#include <algorithm>
+#include <cstdint>
+#include <cmath>
+#include <utility>
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/ServoStyleConsts.h"
+#include "nsString.h"
+
+/*
+ * This file is separate from gfxFont.h so that layout can include it
+ * without bringing in gfxFont.h and everything it includes.
+ */
+
+namespace mozilla {
+
+using FontSlantStyle = StyleFontStyle;
+using FontWeight = StyleFontWeight;
+using FontStretch = StyleFontStretch;
+
+/**
+ * Convenience type to hold a <min, max> pair representing a range of values.
+ *
+ * The min and max are both inclusive, so when min == max the range represents
+ * a single value (not an empty range).
+ */
+template <class T, class Derived>
+class FontPropertyRange {
+  // This implementation assumes the underlying property type is a 16-bit value
+  // (see FromScalar and AsScalar below).
+  static_assert(sizeof(T) == 2, "FontPropertyValue should be a 16-bit type!");
+
+ public:
+  /**
+   * Construct a range from given minimum and maximum values (inclusive).
+   */
+  FontPropertyRange(T aMin, T aMax) : mValues(aMin, aMax) {
+    MOZ_ASSERT(aMin <= aMax);
+  }
+
+  /**
+   * Construct a range representing a single value (min==max).
+   */
+  explicit FontPropertyRange(T aValue) : mValues(aValue, aValue) {}
+
+  explicit FontPropertyRange(const FontPropertyRange& aOther) = default;
+  FontPropertyRange& operator=(const FontPropertyRange& aOther) = default;
+
+  T Min() const { return mValues.first; }
+  T Max() const { return mValues.second; }
+
+  /**
+   * Clamp the given value to this range.
+   *
+   * (We can't use mozilla::Clamp here because it only accepts integral types.)
+   */
+  T Clamp(T aValue) const {
+    return aValue <= Min() ? Min() : (aValue >= Max() ? Max() : aValue);
+  }
+
+  /**
+   * Return whether the range consists of a single unique value.
+   */
+  bool IsSingle() const { return Min() == Max(); }
+
+  bool operator==(const FontPropertyRange& aOther) const {
+    return mValues == aOther.mValues;
+  }
+  bool operator!=(const FontPropertyRange& aOther) const {
+    return mValues != aOther.mValues;
+  }
+
+  /**
+   * Conversion of the property range to/from a single 32-bit scalar value,
+   * suitable for IPC serialization, hashing, caching.
+   *
+   * No assumptions should be made about the numeric value of the scalar.
+   *
+   * This depends on the underlying property type being a 16-bit value!
+   */
+  using ScalarType = uint32_t;
+
+  ScalarType AsScalar() const {
+    return (mValues.first.UnsignedRaw() << 16) | mValues.second.UnsignedRaw();
+  }
+
+  static Derived FromScalar(ScalarType aScalar) {
+    static_assert(std::is_base_of_v<FontPropertyRange, Derived>);
+    return Derived(T::FromRaw(aScalar >> 16), T::FromRaw(aScalar & 0xffff));
+  }
+
+ protected:
+  std::pair<T, T> mValues;
+};
+
+class WeightRange : public FontPropertyRange<FontWeight, WeightRange> {
+ public:
+  WeightRange(FontWeight aMin, FontWeight aMax)
+      : FontPropertyRange(aMin, aMax) {}
+
+  explicit WeightRange(FontWeight aWeight) : FontPropertyRange(aWeight) {}
+
+  WeightRange(const WeightRange& aOther) = default;
+
+  void ToString(nsACString& aOutString, const char* aDelim = "..") const {
+    aOutString.AppendFloat(Min().ToFloat());
+    if (!IsSingle()) {
+      aOutString.Append(aDelim);
+      aOutString.AppendFloat(Max().ToFloat());
+    }
+  }
+};
+
+class StretchRange : public FontPropertyRange<FontStretch, StretchRange> {
+ public:
+  StretchRange(FontStretch aMin, FontStretch aMax)
+      : FontPropertyRange(aMin, aMax) {}
+
+  explicit StretchRange(FontStretch aStretch) : FontPropertyRange(aStretch) {}
+
+  StretchRange(const StretchRange& aOther) = default;
+
+  void ToString(nsACString& aOutString, const char* aDelim = "..") const {
+    aOutString.AppendFloat(Min().ToFloat());
+    if (!IsSingle()) {
+      aOutString.Append(aDelim);
+      aOutString.AppendFloat(Max().ToFloat());
+    }
+  }
+};
+
+class SlantStyleRange
+    : public FontPropertyRange<FontSlantStyle, SlantStyleRange> {
+ public:
+  SlantStyleRange(FontSlantStyle aMin, FontSlantStyle aMax)
+      : FontPropertyRange(aMin, aMax) {}
+
+  explicit SlantStyleRange(FontSlantStyle aStyle) : FontPropertyRange(aStyle) {}
+
+  SlantStyleRange(const SlantStyleRange& aOther) = default;
+
+  void ToString(nsACString& aOutString, const char* aDelim = "..") const {
+    Min().ToString(aOutString);
+    if (!IsSingle()) {
+      aOutString.Append(aDelim);
+      Max().ToString(aOutString);
+    }
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // GFX_FONT_PROPERTY_TYPES_H
diff --git a/gfx/src/RegionBuilder.h b/gfx/src/RegionBuilder.h
new file mode 100644
index 0000000000..4913c43619
--- /dev/null
+++ b/gfx/src/RegionBuilder.h
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ *  * License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef RegionBuilder_h__
+#define RegionBuilder_h__
+
+#include "nsTArray.h"
+#include "pixman.h"
+
+template <typename RegionType>
+class RegionBuilder {
+ public:
+  typedef typename RegionType::RectType RectType;
+
+  RegionBuilder() = default;
+
+  void OrWith(const RectType& aRect) {
+    pixman_box32_t box = {aRect.X(), aRect.Y(), aRect.XMost(), aRect.YMost()};
+    mRects.AppendElement(box);
+  }
+
+  RegionType ToRegion() const { return RegionType(mRects); }
+
+ private:
+  nsTArray<pixman_box32_t> mRects;
+};
+
+#endif  // RegionBuilder_h__
diff --git a/gfx/src/RelativeLuminanceUtils.h b/gfx/src/RelativeLuminanceUtils.h
new file mode 100644
index 0000000000..34e3ccf6da
--- /dev/null
+++ b/gfx/src/RelativeLuminanceUtils.h
@@ -0,0 +1,78 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_RelativeLuminanceUtils_h
+#define mozilla_RelativeLuminanceUtils_h
+
+#include "nsColor.h"
+
+namespace mozilla {
+
+// Utilities for calculating relative luminance based on the algorithm
+// defined in https://www.w3.org/TR/WCAG20/#relativeluminancedef
+class RelativeLuminanceUtils {
+ public:
+  // Compute the relative luminance.
+  static float Compute(nscolor aColor) {
+    float r = ComputeComponent(NS_GET_R(aColor));
+    float g = ComputeComponent(NS_GET_G(aColor));
+    float b = ComputeComponent(NS_GET_B(aColor));
+    return ComputeFromComponents(r, g, b);
+  }
+
+  // Adjust the relative luminance of the given color.
+  static nscolor Adjust(nscolor aColor, float aLuminance) {
+    float r = ComputeComponent(NS_GET_R(aColor));
+    float g = ComputeComponent(NS_GET_G(aColor));
+    float b = ComputeComponent(NS_GET_B(aColor));
+    float luminance = ComputeFromComponents(r, g, b);
+    float factor = (aLuminance + 0.05f) / (luminance + 0.05f);
+    uint8_t r1 =
+        DecomputeComponent(std::max(0.0f, (r + 0.05f) * factor - 0.05f));
+    uint8_t g1 =
+        DecomputeComponent(std::max(0.0f, (g + 0.05f) * factor - 0.05f));
+    uint8_t b1 =
+        DecomputeComponent(std::max(0.0f, (b + 0.05f) * factor - 0.05f));
+    return NS_RGBA(r1, g1, b1, NS_GET_A(aColor));
+  }
+
+  // https://www.w3.org/TR/WCAG21/#dfn-contrast-ratio
+  static float ContrastRatio(nscolor aColor1, nscolor aColor2) {
+    float l1 = Compute(aColor1);
+    float l2 = Compute(aColor2);
+    if (l1 < l2) {
+      std::swap(l1, l2);
+    }
+    return (l1 + 0.05f) / (l2 + 0.05f);
+  }
+
+ private:
+  static float ComputeComponent(uint8_t aComponent) {
+    float v = float(aComponent) / 255.0f;
+    if (v <= 0.03928f) {
+      return v / 12.92f;
+    }
+    return std::pow((v + 0.055f) / 1.055f, 2.4f);
+  }
+
+  static constexpr float ComputeFromComponents(float aR, float aG, float aB) {
+    return 0.2126f * aR + 0.7152f * aG + 0.0722f * aB;
+  }
+
+  // Inverse function of ComputeComponent.
+  static uint8_t DecomputeComponent(float aComponent) {
+    if (aComponent <= 0.03928f / 12.92f) {
+      aComponent *= 12.92f;
+    } else {
+      aComponent = std::pow(aComponent, 1.0f / 2.4f) * 1.055f - 0.055f;
+    }
+    return ClampColor(aComponent * 255.0f);
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_RelativeLuminanceUtils_h
diff --git a/gfx/src/WPFGpuRaster.h b/gfx/src/WPFGpuRaster.h
new file mode 100644
index 0000000000..e10f21bf6d
--- /dev/null
+++ b/gfx/src/WPFGpuRaster.h
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_GFX_WPF_GPU_RASTER_H
+#define MOZILLA_GFX_WPF_GPU_RASTER_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+namespace WGR {
+
+enum class FillMode { EvenOdd, Winding };
+struct PathBuilder;
+struct Point {
+  int32_t x;
+  int32_t y;
+};
+constexpr uint8_t PathPointTypeStart = 0;
+constexpr uint8_t PathPointTypeLine = 1;
+constexpr uint8_t PathPointTypeBezier = 3;
+constexpr uint8_t PathPointTypePathTypeMask = 0x07;
+constexpr uint8_t PathPointTypeCloseSubpath = 0x80;
+struct Path {
+  FillMode fill_mode;
+  const Point* points;
+  size_t num_points;
+  const uint8_t* types;
+  size_t num_types;
+};
+struct OutputVertex {
+  float x;
+  float y;
+  float coverage;
+};
+struct VertexBuffer {
+  OutputVertex* data;
+  size_t len;
+};
+
+extern "C" {
+PathBuilder* wgr_new_builder();
+void wgr_builder_move_to(PathBuilder* pb, float x, float y);
+void wgr_builder_line_to(PathBuilder* pb, float x, float y);
+void wgr_builder_curve_to(PathBuilder* pb, float c1x, float c1y, float c2x,
+                          float c2y, float x, float y);
+void wgr_builder_quad_to(PathBuilder* pb, float cx, float cy, float x, float y);
+void wgr_builder_close(PathBuilder* pb);
+void wgr_builder_set_fill_mode(PathBuilder* pb, FillMode fill_mode);
+Path wgr_builder_get_path(PathBuilder* pb);
+VertexBuffer wgr_path_rasterize_to_tri_list(
+    const Path* p, int32_t clip_x, int32_t clip_y, int32_t clip_width,
+    int32_t clip_height, bool need_inside = true, bool need_outside = false,
+    bool rasterization_truncates = false, OutputVertex* output_ptr = nullptr,
+    size_t output_capacity = 0);
+void wgr_path_release(Path p);
+void wgr_vertex_buffer_release(VertexBuffer vb);
+void wgr_builder_release(PathBuilder* pb);
+};
+
+}  // namespace WGR
+
+#endif  // MOZILLA_GFX_WPF_GPU_RASTER_H
diff --git a/gfx/src/X11UndefineNone.h b/gfx/src/X11UndefineNone.h
new file mode 100644
index 0000000000..3f0c4aef31
--- /dev/null
+++ b/gfx/src/X11UndefineNone.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// The header <X11/X.h> defines "None" as a macro that expands to "0L".
+// This is terrible because many enumerations have an enumerator named "None".
+// To work around this, we undefine the macro "None", and define a replacement
+// macro named "X11None".
+// Include this header after including X11 headers, where necessary.
+#ifdef None
+#  undef None
+#  define X11None 0L
+// <X11/X.h> also defines "RevertToNone" as a macro that expands to "(int)None".
+// Since we are undefining "None", that stops working. To keep it working,
+// we undefine "RevertToNone" and redefine it in terms of "X11None".
+#  ifdef RevertToNone
+#    undef RevertToNone
+#    define RevertToNone (int)X11None
+#  endif
+#endif
+
+// X11 also defines Always, which conflicts with some style system enum variant
+// names, so get rid of that too, given we don't use it anywhere else.
+#ifdef Always
+#  undef Always
+#endif
+
+// And Complex...
+#ifdef Complex
+#  undef Complex
+#endif
+
+#ifdef CurrentTime
+#  undef CurrentTime
+#  define X11CurrentTime 0L
+#endif
+
+// X11/Xlib.h also defines True and False, get rid of those too for
+// the same reasons as above...
+#ifdef True
+#  undef True
+#  define X11True 1
+#endif
+#ifdef False
+#  undef False
+#  define X11False 0
+#endif
diff --git a/gfx/src/X11Util.cpp b/gfx/src/X11Util.cpp
new file mode 100644
index 0000000000..90ad08202b
--- /dev/null
+++ b/gfx/src/X11Util.cpp
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "X11Util.h"
+#include "nsDebug.h"          // for NS_ASSERTION, etc
+#include "MainThreadUtils.h"  // for NS_IsMainThread
+
+namespace mozilla {
+
+void FindVisualAndDepth(Display* aDisplay, VisualID aVisualID, Visual** aVisual,
+                        int* aDepth) {
+  const Screen* screen = DefaultScreenOfDisplay(aDisplay);
+
+  for (int d = 0; d < screen->ndepths; d++) {
+    Depth* d_info = &screen->depths[d];
+    for (int v = 0; v < d_info->nvisuals; v++) {
+      Visual* visual = &d_info->visuals[v];
+      if (visual->visualid == aVisualID) {
+        *aVisual = visual;
+        *aDepth = d_info->depth;
+        return;
+      }
+    }
+  }
+
+  NS_ASSERTION(aVisualID == X11None, "VisualID not on Screen.");
+  *aVisual = nullptr;
+  *aDepth = 0;
+}
+
+void FinishX(Display* aDisplay) {
+  unsigned long lastRequest = NextRequest(aDisplay) - 1;
+  if (lastRequest == LastKnownRequestProcessed(aDisplay)) return;
+
+  XSync(aDisplay, X11False);
+}
+
+}  // namespace mozilla
diff --git a/gfx/src/X11Util.h b/gfx/src/X11Util.h
new file mode 100644
index 0000000000..e7e09f93fa
--- /dev/null
+++ b/gfx/src/X11Util.h
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_X11Util_h
+#define mozilla_X11Util_h
+
+// Utilities common to all X clients, regardless of UI toolkit.
+
+#if defined(MOZ_WIDGET_GTK)
+#  include <gdk/gdk.h>
+#  include <gdk/gdkx.h>
+#  include "mozilla/WidgetUtilsGtk.h"
+#  include "X11UndefineNone.h"
+#else
+#  error Unknown toolkit
+#endif
+
+#include <string.h>          // for memset
+#include "mozilla/Scoped.h"  // for SCOPED_TEMPLATE
+
+namespace mozilla {
+
+/**
+ * Return the default X Display created and used by the UI toolkit.
+ */
+inline Display* DefaultXDisplay() {
+#if defined(MOZ_WIDGET_GTK)
+  GdkDisplay* gdkDisplay = gdk_display_get_default();
+  if (mozilla::widget::GdkIsX11Display(gdkDisplay)) {
+    return GDK_DISPLAY_XDISPLAY(gdkDisplay);
+  }
+#endif
+  return nullptr;
+}
+
+/**
+ * Sets *aVisual to point to aDisplay's Visual struct corresponding to
+ * aVisualID, and *aDepth to its depth.  When aVisualID is None, these are set
+ * to nullptr and 0 respectively.  Both out-parameter pointers are assumed
+ * non-nullptr.
+ */
+void FindVisualAndDepth(Display* aDisplay, VisualID aVisualID, Visual** aVisual,
+                        int* aDepth);
+
+/**
+ * Ensure that all X requests have been processed.
+ *
+ * This is similar to XSync, but doesn't need a round trip if the previous
+ * request was synchronous or if events have been received since the last
+ * request.  Subsequent FinishX calls will be noops if there have been no
+ * intermediate requests.
+ */
+
+void FinishX(Display* aDisplay);
+
+/**
+ * Invoke XFree() on a pointer to memory allocated by Xlib (if the
+ * pointer is nonnull) when this class goes out of scope.
+ */
+template <typename T>
+struct ScopedXFreePtrTraits {
+  typedef T* type;
+  static T* empty() { return nullptr; }
+  static void release(T* ptr) {
+    if (ptr != nullptr) XFree(ptr);
+  }
+};
+SCOPED_TEMPLATE(ScopedXFree, ScopedXFreePtrTraits)
+
+}  // namespace mozilla
+
+#endif  // mozilla_X11Util_h
diff --git a/gfx/src/components.conf b/gfx/src/components.conf
new file mode 100644
index 0000000000..d1c5d69351
--- /dev/null
+++ b/gfx/src/components.conf
@@ -0,0 +1,14 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Classes = [
+    {
+        'cid': '{a6cf9115-15b3-11d2-932e-00805f8add32}',
+        'contract_ids': ['@mozilla.org/gfx/fontenumerator;1'],
+        'type': 'nsThebesFontEnumerator',
+        'headers': ['/gfx/src/nsThebesFontEnumerator.h'],
+    },
+]
diff --git a/gfx/src/gfxCrashReporterUtils.cpp b/gfx/src/gfxCrashReporterUtils.cpp
new file mode 100644
index 0000000000..dcc97c2f08
--- /dev/null
+++ b/gfx/src/gfxCrashReporterUtils.cpp
@@ -0,0 +1,127 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gfxCrashReporterUtils.h"
+#include <string.h>                  // for strcmp
+#include "mozilla/Assertions.h"      // for MOZ_ASSERT_HELPER2
+#include "mozilla/SchedulerGroup.h"  // for SchedulerGroup
+#include "mozilla/Services.h"        // for GetObserverService
+#include "mozilla/StaticMutex.h"
+#include "mozilla/mozalloc.h"    // for operator new, etc
+#include "mozilla/RefPtr.h"      // for RefPtr
+#include "MainThreadUtils.h"     // for NS_IsMainThread
+#include "nsCOMPtr.h"            // for nsCOMPtr
+#include "nsError.h"             // for NS_OK, NS_FAILED, nsresult
+#include "nsExceptionHandler.h"  // for AppendAppNotesToCrashReport
+#include "nsID.h"
+#include "nsIObserver.h"         // for nsIObserver, etc
+#include "nsIObserverService.h"  // for nsIObserverService
+#include "nsIRunnable.h"         // for nsIRunnable
+#include "nsISupports.h"
+#include "nsTArray.h"  // for nsTArray
+#include "nscore.h"    // for NS_IMETHOD, NS_IMETHODIMP, etc
+
+namespace mozilla {
+
+static nsTArray<nsCString>* gFeaturesAlreadyReported = nullptr;
+static StaticMutex gFeaturesAlreadyReportedMutex MOZ_UNANNOTATED;
+
+class ObserverToDestroyFeaturesAlreadyReported final : public nsIObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  ObserverToDestroyFeaturesAlreadyReported() = default;
+
+ private:
+  virtual ~ObserverToDestroyFeaturesAlreadyReported() = default;
+};
+
+NS_IMPL_ISUPPORTS(ObserverToDestroyFeaturesAlreadyReported, nsIObserver)
+
+NS_IMETHODIMP
+ObserverToDestroyFeaturesAlreadyReported::Observe(nsISupports* aSubject,
+                                                  const char* aTopic,
+                                                  const char16_t* aData) {
+  if (!strcmp(aTopic, "xpcom-shutdown")) {
+    StaticMutexAutoLock al(gFeaturesAlreadyReportedMutex);
+    if (gFeaturesAlreadyReported) {
+      delete gFeaturesAlreadyReported;
+      gFeaturesAlreadyReported = nullptr;
+    }
+  }
+  return NS_OK;
+}
+
+class RegisterObserverRunnable : public Runnable {
+ public:
+  RegisterObserverRunnable() : Runnable("RegisterObserverRunnable") {}
+  NS_IMETHOD Run() override {
+    // LeakLog made me do this. Basically, I just wanted
+    // gFeaturesAlreadyReported to be a static nsTArray<nsCString>, and LeakLog
+    // was complaining about leaks like this:
+    //    leaked 1 instance of nsTArray_base with size 8 bytes
+    //    leaked 7 instances of nsStringBuffer with size 8 bytes each (56 bytes
+    //    total)
+    // So this is a work-around using a pointer, and using a nsIObserver to
+    // deallocate on xpcom shutdown. Yay for fighting bloat.
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    if (!observerService) return NS_OK;
+    RefPtr<ObserverToDestroyFeaturesAlreadyReported> observer =
+        new ObserverToDestroyFeaturesAlreadyReported;
+    observerService->AddObserver(observer, "xpcom-shutdown", false);
+    return NS_OK;
+  }
+};
+
+class AppendAppNotesRunnable : public Runnable {
+ public:
+  explicit AppendAppNotesRunnable(const nsACString& aFeatureStr)
+      : Runnable("AppendAppNotesRunnable"), mFeatureString(aFeatureStr) {}
+
+  NS_IMETHOD Run() override {
+    CrashReporter::AppendAppNotesToCrashReport(mFeatureString);
+    return NS_OK;
+  }
+
+ private:
+  nsAutoCString mFeatureString;
+};
+
+void ScopedGfxFeatureReporter::WriteAppNote(char statusChar,
+                                            int32_t statusNumber) {
+  StaticMutexAutoLock al(gFeaturesAlreadyReportedMutex);
+
+  if (!gFeaturesAlreadyReported) {
+    gFeaturesAlreadyReported = new nsTArray<nsCString>;
+    nsCOMPtr<nsIRunnable> r = new RegisterObserverRunnable();
+    SchedulerGroup::Dispatch(TaskCategory::Other, r.forget());
+  }
+
+  nsAutoCString featureString;
+  if (statusNumber == 0) {
+    featureString.AppendPrintf("%s%c ", mFeature, statusChar);
+  } else {
+    featureString.AppendPrintf("%s%c%d ", mFeature, statusChar, statusNumber);
+  }
+
+  if (!gFeaturesAlreadyReported->Contains(featureString)) {
+    gFeaturesAlreadyReported->AppendElement(featureString);
+    AppNote(featureString);
+  }
+}
+
+void ScopedGfxFeatureReporter::AppNote(const nsACString& aMessage) {
+  if (NS_IsMainThread()) {
+    CrashReporter::AppendAppNotesToCrashReport(aMessage);
+  } else {
+    nsCOMPtr<nsIRunnable> r = new AppendAppNotesRunnable(aMessage);
+    SchedulerGroup::Dispatch(TaskCategory::Other, r.forget());
+  }
+}
+
+}  // end namespace mozilla
diff --git a/gfx/src/gfxCrashReporterUtils.h b/gfx/src/gfxCrashReporterUtils.h
new file mode 100644
index 0000000000..30b670df61
--- /dev/null
+++ b/gfx/src/gfxCrashReporterUtils.h
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef gfxCrashReporterUtils_h__
+#define gfxCrashReporterUtils_h__
+
+#include "nsString.h"
+
+namespace mozilla {
+
+/** \class ScopedGfxFeatureReporter
+ *
+ * On creation, adds "FeatureName?" to AppNotes
+ * On destruction, adds "FeatureName-", or "FeatureName+" if you called
+ * SetSuccessful().
+ *
+ * Any such string is added at most once to AppNotes, and is subsequently
+ * skipped.
+ *
+ * This ScopedGfxFeatureReporter class is designed to be fool-proof to use in
+ * functions that have many exit points. We don't want to encourage having
+ * function with many exit points. It just happens that our graphics features
+ * initialization functions are like that.
+ */
+class ScopedGfxFeatureReporter {
+ public:
+  explicit ScopedGfxFeatureReporter(const char* aFeature, bool aForce = false)
+      : mFeature(aFeature), mStatusChar('-'), mStatusNumber(0) {
+    WriteAppNote(aForce ? '!' : '?', 0);
+  }
+  ~ScopedGfxFeatureReporter() { WriteAppNote(mStatusChar, mStatusNumber); }
+  void SetSuccessful() { mStatusChar = '+'; }
+  void SetSuccessful(int32_t aNumber) {
+    mStatusChar = '+';
+    mStatusNumber = aNumber;
+  }
+
+  static void AppNote(const nsACString& aMessage);
+
+  class AppNoteWritingRunnable;
+
+ protected:
+  const char* mFeature;
+  char mStatusChar;
+  int32_t mStatusNumber;
+
+ private:
+  void WriteAppNote(char statusChar, int32_t statusNumber);
+};
+
+}  // end namespace mozilla
+
+#endif  // gfxCrashReporterUtils_h__
diff --git a/gfx/src/gfxTelemetry.cpp b/gfx/src/gfxTelemetry.cpp
new file mode 100644
index 0000000000..f434164c40
--- /dev/null
+++ b/gfx/src/gfxTelemetry.cpp
@@ -0,0 +1,97 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "gfxTelemetry.h"
+
+#include "mozilla/Assertions.h"
+
+namespace mozilla {
+namespace gfx {
+
+const char* FeatureStatusToString(FeatureStatus aStatus) {
+  switch (aStatus) {
+    case FeatureStatus::Unused:
+      return "unused";
+    case FeatureStatus::Unavailable:
+      return "unavailable";
+    case FeatureStatus::UnavailableInSafeMode:
+      return "unavailable-in-safe-mode";
+    case FeatureStatus::UnavailableNoGpuProcess:
+      return "unavailable-no-gpu-process";
+    case FeatureStatus::UnavailableNoHwCompositing:
+      return "unavailable-no-hw-compositing";
+    case FeatureStatus::UnavailableNotBuilt:
+      return "unavailable-not-built";
+    case FeatureStatus::UnavailableNoAngle:
+      return "unavailable-no-angle";
+    case FeatureStatus::UnavailableNoWebRender:
+      return "unavailable-no-webrender";
+    case FeatureStatus::CrashedInHandler:
+      return "crashed";
+    case FeatureStatus::Blocked:
+      return "blocked";
+    case FeatureStatus::BlockedDeviceUnknown:
+      return "blocked-device-unknown";
+    case FeatureStatus::BlockedDeviceTooOld:
+      return "blocked-device-too-old";
+    case FeatureStatus::BlockedVendorUnsupported:
+      return "blocked-vendor-unsupported";
+    case FeatureStatus::BlockedHasBattery:
+      return "blocked-has-battery";
+    case FeatureStatus::BlockedScreenTooLarge:
+      return "blocked-screen-too-large";
+    case FeatureStatus::BlockedScreenUnknown:
+      return "blocked-screen-unknown";
+    case FeatureStatus::BlockedNoGfxInfo:
+      return "blocked-no-gfx-info";
+    case FeatureStatus::BlockedOverride:
+      return "blocked-override";
+    case FeatureStatus::BlockedReleaseChannelIntel:
+      return "blocked-release-channel-intel";
+    case FeatureStatus::BlockedReleaseChannelAMD:
+      return "blocked-release-channel-amd";
+    case FeatureStatus::BlockedReleaseChannelNvidia:
+      return "blocked-release-channel-nvidia";
+    case FeatureStatus::BlockedReleaseChannelBattery:
+      return "blocked-release-channel-battery";
+    case FeatureStatus::BlockedReleaseChannelAndroid:
+      return "blocked-release-channel-android";
+    case FeatureStatus::Denied:
+      return "denied";
+    case FeatureStatus::Blocklisted:
+      return "blocklisted";
+    case FeatureStatus::OptIn:
+      return "opt-in";
+    case FeatureStatus::Failed:
+      return "failed";
+    case FeatureStatus::Disabled:
+      return "disabled";
+    case FeatureStatus::Available:
+      return "available";
+    case FeatureStatus::ForceEnabled:
+      return "force_enabled";
+    case FeatureStatus::CrashedOnStartup:
+      return "crashed_on_startup";
+    case FeatureStatus::Broken:
+      return "broken";
+    default:
+      MOZ_ASSERT_UNREACHABLE("missing status case");
+      return "unknown";
+  }
+}
+
+bool IsFeatureStatusFailure(FeatureStatus aStatus) {
+  return !(aStatus == FeatureStatus::Unused ||
+           aStatus == FeatureStatus::Available ||
+           aStatus == FeatureStatus::ForceEnabled);
+}
+
+bool IsFeatureStatusSuccess(FeatureStatus aStatus) {
+  return aStatus == FeatureStatus::Available ||
+         aStatus == FeatureStatus::ForceEnabled;
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/src/gfxTelemetry.h b/gfx/src/gfxTelemetry.h
new file mode 100644
index 0000000000..37d603674a
--- /dev/null
+++ b/gfx/src/gfxTelemetry.h
@@ -0,0 +1,93 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef gfx_src_gfxTelemetry_h__
+#define gfx_src_gfxTelemetry_h__
+
+#include <cstdint>
+
+namespace mozilla {
+namespace gfx {
+
+// Describes the status of a graphics feature, in terms of whether or not we've
+// attempted to initialize the feature, and if so, whether or not it succeeded
+// (and if not, why).
+enum class FeatureStatus {
+  // This feature has not been requested.
+  Unused,
+
+  // This feature is unavailable due to Safe Mode, not being included with
+  // the operating system, or a dependent feature being disabled.
+  Unavailable,
+  UnavailableInSafeMode,
+  UnavailableNoGpuProcess,
+  UnavailableNoHwCompositing,
+  UnavailableNotBuilt,
+  UnavailableNoAngle,
+  UnavailableNoWebRender,
+
+  // This feature crashed immediately when we tried to initialize it, but we
+  // were able to recover via SEH (or something similar).
+  CrashedInHandler,
+
+  // This feature was blocked for reasons outside the blocklist, such as a
+  // runtime test failing.
+  Blocked,
+  BlockedDeviceUnknown,
+  BlockedDeviceTooOld,
+  BlockedVendorUnsupported,
+  BlockedHasBattery,
+  BlockedScreenTooLarge,
+  BlockedScreenUnknown,
+  BlockedNoGfxInfo,
+  BlockedOverride,
+  BlockedReleaseChannelIntel,
+  BlockedReleaseChannelAMD,
+  BlockedReleaseChannelNvidia,
+  BlockedReleaseChannelBattery,
+  BlockedReleaseChannelAndroid,
+
+  // This feature has been blocked by the allowlist.
+  Denied,
+
+  // This feature has been blocked by the graphics blocklist.
+  Blocklisted,
+
+  // This feature is disabled by default, and so activation isn't attempted
+  // unless something explicitly enables it.
+  OptIn,
+
+  // This feature was attempted but failed to activate.
+  Failed,
+
+  // This feature was explicitly disabled by the user.
+  Disabled,
+
+  // This feature is available for use.
+  Available,
+
+  // This feature was explicitly force-enabled by the user.
+  ForceEnabled,
+
+  // This feature was disabled due to the startup crash guard.
+  CrashedOnStartup,
+
+  // This feature was attempted but later determined to be broken.
+  Broken,
+
+  // Add new entries above here.
+  LAST
+};
+
+const char* FeatureStatusToString(FeatureStatus aStatus);
+bool IsFeatureStatusFailure(FeatureStatus aStatus);
+bool IsFeatureStatusSuccess(FeatureStatus aStatus);
+
+enum class TelemetryDeviceCode : uint32_t { Content = 0, Image = 1, D2D1 = 2 };
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // gfx_src_gfxTelemetry_h__
diff --git a/gfx/src/moz.build b/gfx/src/moz.build
new file mode 100644
index 0000000000..48b9c44039
--- /dev/null
+++ b/gfx/src/moz.build
@@ -0,0 +1,98 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+XPIDL_SOURCES += [
+    "nsIFontEnumerator.idl",
+]
+
+XPIDL_MODULE = "gfx"
+
+DEFINES["MOZ_APP_VERSION"] = '"%s"' % CONFIG["MOZ_APP_VERSION"]
+
+EXPORTS += [
+    "DriverCrashGuard.h",
+    "FilterDescription.h",
+    "FilterSupport.h",
+    "gfxCrashReporterUtils.h",
+    "gfxTelemetry.h",
+    "nsBoundingMetrics.h",
+    "nsColor.h",
+    "nsColorNameList.h",
+    "nsColorNames.h",
+    "nsCoord.h",
+    "nsDeviceContext.h",
+    "nsFont.h",
+    "nsFontCache.h",
+    "nsFontMetrics.h",
+    "nsGfxCIID.h",
+    "nsITheme.h",
+    "nsMargin.h",
+    "nsPoint.h",
+    "nsRect.h",
+    "nsRectAbsolute.h",
+    "nsRegion.h",
+    "nsRegionFwd.h",
+    "nsSize.h",
+    "nsTransform2D.h",
+    "RegionBuilder.h",
+    "X11UndefineNone.h",
+]
+
+EXPORTS.mozilla += [
+    "AppUnits.h",
+    "ArrayView.h",
+    "FontPropertyTypes.h",
+    "RelativeLuminanceUtils.h",
+]
+
+EXPORTS.mozilla.gfx += [
+    "AAStroke.h",
+    "CompositorHitTestInfo.h",
+    "WPFGpuRaster.h",
+]
+
+if CONFIG["MOZ_X11"]:
+    EXPORTS.mozilla += ["X11Util.h"]
+    SOURCES += [
+        "X11Util.cpp",
+    ]
+
+UNIFIED_SOURCES += [
+    "DriverCrashGuard.cpp",
+    "FilterSupport.cpp",
+    "gfxCrashReporterUtils.cpp",
+    "gfxTelemetry.cpp",
+    "nsColor.cpp",
+    "nsFont.cpp",
+    "nsFontCache.cpp",
+    "nsFontMetrics.cpp",
+    "nsRect.cpp",
+    "nsRegion.cpp",
+    "nsThebesFontEnumerator.cpp",
+    "nsTransform2D.cpp",
+]
+
+# nsDeviceContext.cpp cannot be built in unified mode because it pulls in OS X system headers.
+SOURCES += [
+    "nsDeviceContext.cpp",
+]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+LOCAL_INCLUDES += [
+    "/dom/ipc",  # for ContentChild.h
+    "/gfx/cairo/cairo/src",
+]
+
+FINAL_LIBRARY = "xul"
+
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
+    CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+    CXXFLAGS += CONFIG["MOZ_PANGO_CFLAGS"]
diff --git a/gfx/src/nsBoundingMetrics.h b/gfx/src/nsBoundingMetrics.h
new file mode 100644
index 0000000000..e937dc1870
--- /dev/null
+++ b/gfx/src/nsBoundingMetrics.h
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsBoundingMetrics_h
+#define __nsBoundingMetrics_h
+
+#include "nsCoord.h"
+#include <algorithm>
+
+/* Struct used for accurate measurements of a string, in order to
+ * allow precise positioning when processing MathML.  This is in its
+ * own header file because some very-widely-included headers need it
+ * but not the rest of nsFontMetrics, or vice versa.
+ */
+
+struct nsBoundingMetrics {
+  ///////////
+  // Metrics that _exactly_ enclose the text:
+
+  // The character coordinate system is the one used on X Windows:
+  // 1. The origin is located at the intersection of the baseline
+  //    with the left of the character's cell.
+  // 2. All horizontal bearings are oriented from left to right.
+  // 2. All horizontal bearings are oriented from left to right.
+  // 3. The ascent is oriented from bottom to top (being 0 at the orgin).
+  // 4. The descent is oriented from top to bottom (being 0 at the origin).
+
+  // Note that Win32/Mac/PostScript use a different convention for
+  // the descent (all vertical measurements are oriented from bottom
+  // to top on these palatforms). Make sure to flip the sign of the
+  // descent on these platforms for cross-platform compatibility.
+
+  // Any of the following member variables listed here can have
+  // positive or negative value.
+
+  nscoord leftBearing;
+  /* The horizontal distance from the origin of the drawing
+     operation to the left-most part of the drawn string. */
+
+  nscoord rightBearing;
+  /* The horizontal distance from the origin of the drawing
+     operation to the right-most part of the drawn string.
+     The _exact_ width of the string is therefore:
+     rightBearing - leftBearing */
+
+  nscoord ascent;
+  /* The vertical distance from the origin of the drawing
+     operation to the top-most part of the drawn string. */
+
+  nscoord descent;
+  /* The vertical distance from the origin of the drawing
+     operation to the bottom-most part of the drawn string.
+     The _exact_ height of the string is therefore:
+     ascent + descent */
+
+  nscoord width;
+  /* The horizontal distance from the origin of the drawing
+     operation to the correct origin for drawing another string
+     to follow the current one. Depending on the font, this
+     could be greater than or less than the right bearing. */
+
+  nsBoundingMetrics()
+      : leftBearing(0), rightBearing(0), ascent(0), descent(0), width(0) {}
+
+  void operator+=(const nsBoundingMetrics& bm) {
+    if (ascent + descent == 0 && rightBearing - leftBearing == 0) {
+      ascent = bm.ascent;
+      descent = bm.descent;
+      leftBearing = width + bm.leftBearing;
+      rightBearing = width + bm.rightBearing;
+    } else {
+      if (ascent < bm.ascent) ascent = bm.ascent;
+      if (descent < bm.descent) descent = bm.descent;
+      leftBearing = std::min(leftBearing, width + bm.leftBearing);
+      rightBearing = std::max(rightBearing, width + bm.rightBearing);
+    }
+    width += bm.width;
+  }
+};
+
+#endif  // __nsBoundingMetrics_h
diff --git a/gfx/src/nsColor.cpp b/gfx/src/nsColor.cpp
new file mode 100644
index 0000000000..841b187438
--- /dev/null
+++ b/gfx/src/nsColor.cpp
@@ -0,0 +1,262 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"  // for ArrayLength
+#include "mozilla/mozalloc.h"    // for operator delete, etc
+#include "mozilla/MathAlgorithms.h"
+
+#include "nsColor.h"
+#include <sys/types.h>     // for int32_t
+#include "nsColorNames.h"  // for nsColorNames
+#include "nsDebug.h"       // for NS_ASSERTION, etc
+#include "nsStaticNameTable.h"
+#include "nsString.h"  // for nsAutoCString, nsString, etc
+#include "nscore.h"    // for nsAString, etc
+#include "prtypes.h"   // for PR_BEGIN_MACRO, etc
+
+using namespace mozilla;
+
+// define an array of all color names
+#define GFX_COLOR(_name, _value) #_name,
+static const char* const kColorNames[] = {
+#include "nsColorNameList.h"
+};
+#undef GFX_COLOR
+
+// define an array of all color name values
+#define GFX_COLOR(_name, _value) _value,
+static const nscolor kColors[] = {
+#include "nsColorNameList.h"
+};
+#undef GFX_COLOR
+
+#define eColorName_COUNT (ArrayLength(kColorNames))
+#define eColorName_UNKNOWN (-1)
+
+static nsStaticCaseInsensitiveNameTable* gColorTable = nullptr;
+
+void nsColorNames::AddRefTable(void) {
+  NS_ASSERTION(!gColorTable, "pre existing array!");
+  if (!gColorTable) {
+    gColorTable =
+        new nsStaticCaseInsensitiveNameTable(kColorNames, eColorName_COUNT);
+  }
+}
+
+void nsColorNames::ReleaseTable(void) {
+  if (gColorTable) {
+    delete gColorTable;
+    gColorTable = nullptr;
+  }
+}
+
+static int ComponentValue(const char16_t* aColorSpec, int aLen, int color,
+                          int dpc) {
+  int component = 0;
+  int index = (color * dpc);
+  if (2 < dpc) {
+    dpc = 2;
+  }
+  while (--dpc >= 0) {
+    char16_t ch = ((index < aLen) ? aColorSpec[index++] : '0');
+    if (('0' <= ch) && (ch <= '9')) {
+      component = (component * 16) + (ch - '0');
+    } else if ((('a' <= ch) && (ch <= 'f')) || (('A' <= ch) && (ch <= 'F'))) {
+      // "ch&7" handles lower and uppercase hex alphabetics
+      component = (component * 16) + (ch & 7) + 9;
+    } else {  // not a hex digit, treat it like 0
+      component = (component * 16);
+    }
+  }
+  return component;
+}
+
+bool NS_HexToRGBA(const nsAString& aColorSpec, nsHexColorType aType,
+                  nscolor* aResult) {
+  const char16_t* buffer = aColorSpec.BeginReading();
+
+  int nameLen = aColorSpec.Length();
+  bool hasAlpha = false;
+  if (nameLen != 3 && nameLen != 6) {
+    if ((nameLen != 4 && nameLen != 8) || aType == nsHexColorType::NoAlpha) {
+      // Improperly formatted color value
+      return false;
+    }
+    hasAlpha = true;
+  }
+
+  // Make sure the digits are legal
+  for (int i = 0; i < nameLen; i++) {
+    char16_t ch = buffer[i];
+    if (((ch >= '0') && (ch <= '9')) || ((ch >= 'a') && (ch <= 'f')) ||
+        ((ch >= 'A') && (ch <= 'F'))) {
+      // Legal character
+      continue;
+    }
+    // Whoops. Illegal character.
+    return false;
+  }
+
+  // Convert the ascii to binary
+  int dpc = ((nameLen <= 4) ? 1 : 2);
+  // Translate components from hex to binary
+  int r = ComponentValue(buffer, nameLen, 0, dpc);
+  int g = ComponentValue(buffer, nameLen, 1, dpc);
+  int b = ComponentValue(buffer, nameLen, 2, dpc);
+  int a;
+  if (hasAlpha) {
+    a = ComponentValue(buffer, nameLen, 3, dpc);
+  } else {
+    a = (dpc == 1) ? 0xf : 0xff;
+  }
+  if (dpc == 1) {
+    // Scale single digit component to an 8 bit value. Replicate the
+    // single digit to compute the new value.
+    r = (r << 4) | r;
+    g = (g << 4) | g;
+    b = (b << 4) | b;
+    a = (a << 4) | a;
+  }
+  NS_ASSERTION((r >= 0) && (r <= 255), "bad r");
+  NS_ASSERTION((g >= 0) && (g <= 255), "bad g");
+  NS_ASSERTION((b >= 0) && (b <= 255), "bad b");
+  NS_ASSERTION((a >= 0) && (a <= 255), "bad a");
+  *aResult = NS_RGBA(r, g, b, a);
+  return true;
+}
+
+// This implements part of the algorithm for legacy behavior described in
+// http://www.whatwg.org/specs/web-apps/current-work/complete/common-microsyntaxes.html#rules-for-parsing-a-legacy-color-value
+bool NS_LooseHexToRGB(const nsString& aColorSpec, nscolor* aResult) {
+  if (aColorSpec.EqualsLiteral("transparent")) {
+    return false;
+  }
+
+  int nameLen = aColorSpec.Length();
+  const char16_t* colorSpec = aColorSpec.get();
+  if (nameLen > 128) {
+    nameLen = 128;
+  }
+
+  if ('#' == colorSpec[0]) {
+    ++colorSpec;
+    --nameLen;
+  }
+
+  // digits per component
+  int dpc = (nameLen + 2) / 3;
+  int newdpc = dpc;
+
+  // Use only the rightmost 8 characters of each component.
+  if (newdpc > 8) {
+    nameLen -= newdpc - 8;
+    colorSpec += newdpc - 8;
+    newdpc = 8;
+  }
+
+  // And then keep trimming characters at the left until we'd trim one
+  // that would leave a nonzero value, but not past 2 characters per
+  // component.
+  while (newdpc > 2) {
+    bool haveNonzero = false;
+    for (int c = 0; c < 3; ++c) {
+      MOZ_ASSERT(c * dpc < nameLen,
+                 "should not pass end of string while newdpc > 2");
+      char16_t ch = colorSpec[c * dpc];
+      if (('1' <= ch && ch <= '9') || ('A' <= ch && ch <= 'F') ||
+          ('a' <= ch && ch <= 'f')) {
+        haveNonzero = true;
+        break;
+      }
+    }
+    if (haveNonzero) {
+      break;
+    }
+    --newdpc;
+    --nameLen;
+    ++colorSpec;
+  }
+
+  // Translate components from hex to binary
+  int r = ComponentValue(colorSpec, nameLen, 0, dpc);
+  int g = ComponentValue(colorSpec, nameLen, 1, dpc);
+  int b = ComponentValue(colorSpec, nameLen, 2, dpc);
+  NS_ASSERTION((r >= 0) && (r <= 255), "bad r");
+  NS_ASSERTION((g >= 0) && (g <= 255), "bad g");
+  NS_ASSERTION((b >= 0) && (b <= 255), "bad b");
+
+  *aResult = NS_RGB(r, g, b);
+  return true;
+}
+
+bool NS_ColorNameToRGB(const nsAString& aColorName, nscolor* aResult) {
+  if (!gColorTable) return false;
+
+  int32_t id = gColorTable->Lookup(aColorName);
+  if (eColorName_UNKNOWN < id) {
+    NS_ASSERTION(uint32_t(id) < eColorName_COUNT,
+                 "gColorTable->Lookup messed up");
+    if (aResult) {
+      *aResult = kColors[id];
+    }
+    return true;
+  }
+  return false;
+}
+
+// Fast approximate division by 255. It has the property that
+// for all 0 <= n <= 255*255, FAST_DIVIDE_BY_255(n) == n/255.
+// But it only uses two adds and two shifts instead of an
+// integer division (which is expensive on many processors).
+//
+// equivalent to target=v/255
+#define FAST_DIVIDE_BY_255(target, v)        \
+  PR_BEGIN_MACRO                             \
+  unsigned tmp_ = v;                         \
+  target = ((tmp_ << 8) + tmp_ + 255) >> 16; \
+  PR_END_MACRO
+
+// Macro to blend two colors
+//
+// equivalent to target = (bg*(255-fgalpha) + fg*fgalpha)/255
+#define MOZ_BLEND(target, bg, fg, fgalpha) \
+  FAST_DIVIDE_BY_255(target, (bg) * (255 - fgalpha) + (fg) * (fgalpha))
+
+nscolor NS_ComposeColors(nscolor aBG, nscolor aFG) {
+  // This function uses colors that are non premultiplied alpha.
+  int r, g, b, a;
+
+  int bgAlpha = NS_GET_A(aBG);
+  int fgAlpha = NS_GET_A(aFG);
+
+  // Compute the final alpha of the blended color
+  // a = fgAlpha + bgAlpha*(255 - fgAlpha)/255;
+  FAST_DIVIDE_BY_255(a, bgAlpha * (255 - fgAlpha));
+  a = fgAlpha + a;
+  int blendAlpha;
+  if (a == 0) {
+    // In this case the blended color is totally trasparent,
+    // we preserve the color information of the foreground color.
+    blendAlpha = 255;
+  } else {
+    blendAlpha = (fgAlpha * 255) / a;
+  }
+  MOZ_BLEND(r, NS_GET_R(aBG), NS_GET_R(aFG), blendAlpha);
+  MOZ_BLEND(g, NS_GET_G(aBG), NS_GET_G(aFG), blendAlpha);
+  MOZ_BLEND(b, NS_GET_B(aBG), NS_GET_B(aFG), blendAlpha);
+
+  return NS_RGBA(r, g, b, a);
+}
+
+const char* NS_RGBToColorName(nscolor aColor) {
+  for (size_t idx = 0; idx < ArrayLength(kColors); ++idx) {
+    if (kColors[idx] == aColor) {
+      return kColorNames[idx];
+    }
+  }
+
+  return nullptr;
+}
diff --git a/gfx/src/nsColor.h b/gfx/src/nsColor.h
new file mode 100644
index 0000000000..e47f5a4575
--- /dev/null
+++ b/gfx/src/nsColor.h
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsColor_h___
+#define nsColor_h___
+
+#include <stdint.h>   // for uint8_t, uint32_t
+#include "nsCoord.h"  // for NSToIntRound
+#include "nsStringFwd.h"
+
+// A color is a 32 bit unsigned integer with four components: R, G, B
+// and A.
+typedef uint32_t nscolor;
+
+// Make a color out of r,g,b values. This assumes that the r,g,b values are
+// properly constrained to 0-255. This also assumes that a is 255.
+#define NS_RGB(_r, _g, _b) \
+  ((nscolor)((255 << 24) | ((_b) << 16) | ((_g) << 8) | (_r)))
+
+// Make a color out of r,g,b,a values. This assumes that the r,g,b,a
+// values are properly constrained to 0-255.
+#define NS_RGBA(_r, _g, _b, _a) \
+  ((nscolor)(((_a) << 24) | ((_b) << 16) | ((_g) << 8) | (_r)))
+
+// Extract color components from nscolor
+#define NS_GET_R(_rgba) ((uint8_t)((_rgba)&0xff))
+#define NS_GET_G(_rgba) ((uint8_t)(((_rgba) >> 8) & 0xff))
+#define NS_GET_B(_rgba) ((uint8_t)(((_rgba) >> 16) & 0xff))
+#define NS_GET_A(_rgba) ((uint8_t)(((_rgba) >> 24) & 0xff))
+
+namespace mozilla {
+
+template <typename T>
+inline uint8_t ClampColor(T aColor) {
+  if (aColor >= 255) {
+    return 255;
+  }
+  if (aColor <= 0) {
+    return 0;
+  }
+  return NSToIntRound(aColor);
+}
+
+}  // namespace mozilla
+
+enum class nsHexColorType : uint8_t {
+  NoAlpha,     // 3 or 6 digit hex colors only
+  AllowAlpha,  // 3, 4, 6, or 8 digit hex colors
+};
+
+// Translate a hex string to a color. Return true if it parses ok,
+// otherwise return false.
+// This accepts the number of digits specified by aType.
+bool NS_HexToRGBA(const nsAString& aBuf, nsHexColorType aType,
+                  nscolor* aResult);
+
+// Compose one NS_RGB color onto another. The result is what
+// you get if you draw aFG on top of aBG with operator OVER.
+nscolor NS_ComposeColors(nscolor aBG, nscolor aFG);
+
+namespace mozilla {
+
+inline uint32_t RoundingDivideBy255(uint32_t n) {
+  // There is an approximate alternative: ((n << 8) + n + 32896) >> 16
+  // But that is actually slower than this simple expression on a modern
+  // machine with a modern compiler.
+  return (n + 127) / 255;
+}
+
+}  // namespace mozilla
+
+// Translate a hex string to a color. Return true if it parses ok,
+// otherwise return false.
+// This version accepts 1 to 9 digits (missing digits are 0)
+bool NS_LooseHexToRGB(const nsString& aBuf, nscolor* aResult);
+
+// There is no function to translate a color to a hex string, because
+// the hex-string syntax does not support transparency.
+
+// Translate a color name to a color. Return true if it parses ok,
+// otherwise return false.
+bool NS_ColorNameToRGB(const nsAString& aBuf, nscolor* aResult);
+
+// Return a color name for the given nscolor.  If there is no color
+// name for it, returns null.  If there are multiple possible color
+// names for the given color, the first one in nsColorNameList.h
+// (which is generally the first one in alphabetical order) will be
+// returned.
+const char* NS_RGBToColorName(nscolor aColor);
+
+#endif /* nsColor_h___ */
diff --git a/gfx/src/nsColorNameList.h b/gfx/src/nsColorNameList.h
new file mode 100644
index 0000000000..dee6dc79c7
--- /dev/null
+++ b/gfx/src/nsColorNameList.h
@@ -0,0 +1,180 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/******
+
+  This file contains the list of all named colors
+  See nsCSSColorNames.h for access to the enum values for colors
+
+  It is designed to be used as inline input to nsCSSColorNames.cpp *only*
+  through the magic of C preprocessing.
+
+  All entries must be enclosed in the macro GFX_COLOR which will have cruel
+  and unusual things done to it
+
+  It is recommended (but not strictly necessary) to keep all entries
+  in alphabetical order
+
+  The first argument to GFX_COLOR is both the enum identifier of the color
+  and the string value
+  The second argument is the sRGBA value for the named color
+
+  'name' entries *must* use only lowercase characters.
+
+  ** Break these invarient and bad things will happen. **
+
+
+ ******/
+
+GFX_COLOR(aliceblue, NS_RGB(240, 248, 255))
+GFX_COLOR(antiquewhite, NS_RGB(250, 235, 215))
+GFX_COLOR(aqua, NS_RGB(0, 255, 255))
+GFX_COLOR(aquamarine, NS_RGB(127, 255, 212))
+GFX_COLOR(azure, NS_RGB(240, 255, 255))
+GFX_COLOR(beige, NS_RGB(245, 245, 220))
+GFX_COLOR(bisque, NS_RGB(255, 228, 196))
+GFX_COLOR(black, NS_RGB(0, 0, 0))
+GFX_COLOR(blanchedalmond, NS_RGB(255, 235, 205))
+GFX_COLOR(blue, NS_RGB(0, 0, 255))
+GFX_COLOR(blueviolet, NS_RGB(138, 43, 226))
+GFX_COLOR(brown, NS_RGB(165, 42, 42))
+GFX_COLOR(burlywood, NS_RGB(222, 184, 135))
+GFX_COLOR(cadetblue, NS_RGB(95, 158, 160))
+GFX_COLOR(chartreuse, NS_RGB(127, 255, 0))
+GFX_COLOR(chocolate, NS_RGB(210, 105, 30))
+GFX_COLOR(coral, NS_RGB(255, 127, 80))
+GFX_COLOR(cornflowerblue, NS_RGB(100, 149, 237))
+GFX_COLOR(cornsilk, NS_RGB(255, 248, 220))
+GFX_COLOR(crimson, NS_RGB(220, 20, 60))
+GFX_COLOR(cyan, NS_RGB(0, 255, 255))
+GFX_COLOR(darkblue, NS_RGB(0, 0, 139))
+GFX_COLOR(darkcyan, NS_RGB(0, 139, 139))
+GFX_COLOR(darkgoldenrod, NS_RGB(184, 134, 11))
+GFX_COLOR(darkgray, NS_RGB(169, 169, 169))
+GFX_COLOR(darkgreen, NS_RGB(0, 100, 0))
+GFX_COLOR(darkgrey, NS_RGB(169, 169, 169))
+GFX_COLOR(darkkhaki, NS_RGB(189, 183, 107))
+GFX_COLOR(darkmagenta, NS_RGB(139, 0, 139))
+GFX_COLOR(darkolivegreen, NS_RGB(85, 107, 47))
+GFX_COLOR(darkorange, NS_RGB(255, 140, 0))
+GFX_COLOR(darkorchid, NS_RGB(153, 50, 204))
+GFX_COLOR(darkred, NS_RGB(139, 0, 0))
+GFX_COLOR(darksalmon, NS_RGB(233, 150, 122))
+GFX_COLOR(darkseagreen, NS_RGB(143, 188, 143))
+GFX_COLOR(darkslateblue, NS_RGB(72, 61, 139))
+GFX_COLOR(darkslategray, NS_RGB(47, 79, 79))
+GFX_COLOR(darkslategrey, NS_RGB(47, 79, 79))
+GFX_COLOR(darkturquoise, NS_RGB(0, 206, 209))
+GFX_COLOR(darkviolet, NS_RGB(148, 0, 211))
+GFX_COLOR(deeppink, NS_RGB(255, 20, 147))
+GFX_COLOR(deepskyblue, NS_RGB(0, 191, 255))
+GFX_COLOR(dimgray, NS_RGB(105, 105, 105))
+GFX_COLOR(dimgrey, NS_RGB(105, 105, 105))
+GFX_COLOR(dodgerblue, NS_RGB(30, 144, 255))
+GFX_COLOR(firebrick, NS_RGB(178, 34, 34))
+GFX_COLOR(floralwhite, NS_RGB(255, 250, 240))
+GFX_COLOR(forestgreen, NS_RGB(34, 139, 34))
+GFX_COLOR(fuchsia, NS_RGB(255, 0, 255))
+GFX_COLOR(gainsboro, NS_RGB(220, 220, 220))
+GFX_COLOR(ghostwhite, NS_RGB(248, 248, 255))
+GFX_COLOR(gold, NS_RGB(255, 215, 0))
+GFX_COLOR(goldenrod, NS_RGB(218, 165, 32))
+GFX_COLOR(gray, NS_RGB(128, 128, 128))
+GFX_COLOR(grey, NS_RGB(128, 128, 128))
+GFX_COLOR(green, NS_RGB(0, 128, 0))
+GFX_COLOR(greenyellow, NS_RGB(173, 255, 47))
+GFX_COLOR(honeydew, NS_RGB(240, 255, 240))
+GFX_COLOR(hotpink, NS_RGB(255, 105, 180))
+GFX_COLOR(indianred, NS_RGB(205, 92, 92))
+GFX_COLOR(indigo, NS_RGB(75, 0, 130))
+GFX_COLOR(ivory, NS_RGB(255, 255, 240))
+GFX_COLOR(khaki, NS_RGB(240, 230, 140))
+GFX_COLOR(lavender, NS_RGB(230, 230, 250))
+GFX_COLOR(lavenderblush, NS_RGB(255, 240, 245))
+GFX_COLOR(lawngreen, NS_RGB(124, 252, 0))
+GFX_COLOR(lemonchiffon, NS_RGB(255, 250, 205))
+GFX_COLOR(lightblue, NS_RGB(173, 216, 230))
+GFX_COLOR(lightcoral, NS_RGB(240, 128, 128))
+GFX_COLOR(lightcyan, NS_RGB(224, 255, 255))
+GFX_COLOR(lightgoldenrodyellow, NS_RGB(250, 250, 210))
+GFX_COLOR(lightgray, NS_RGB(211, 211, 211))
+GFX_COLOR(lightgreen, NS_RGB(144, 238, 144))
+GFX_COLOR(lightgrey, NS_RGB(211, 211, 211))
+GFX_COLOR(lightpink, NS_RGB(255, 182, 193))
+GFX_COLOR(lightsalmon, NS_RGB(255, 160, 122))
+GFX_COLOR(lightseagreen, NS_RGB(32, 178, 170))
+GFX_COLOR(lightskyblue, NS_RGB(135, 206, 250))
+GFX_COLOR(lightslategray, NS_RGB(119, 136, 153))
+GFX_COLOR(lightslategrey, NS_RGB(119, 136, 153))
+GFX_COLOR(lightsteelblue, NS_RGB(176, 196, 222))
+GFX_COLOR(lightyellow, NS_RGB(255, 255, 224))
+GFX_COLOR(lime, NS_RGB(0, 255, 0))
+GFX_COLOR(limegreen, NS_RGB(50, 205, 50))
+GFX_COLOR(linen, NS_RGB(250, 240, 230))
+GFX_COLOR(magenta, NS_RGB(255, 0, 255))
+GFX_COLOR(maroon, NS_RGB(128, 0, 0))
+GFX_COLOR(mediumaquamarine, NS_RGB(102, 205, 170))
+GFX_COLOR(mediumblue, NS_RGB(0, 0, 205))
+GFX_COLOR(mediumorchid, NS_RGB(186, 85, 211))
+GFX_COLOR(mediumpurple, NS_RGB(147, 112, 219))
+GFX_COLOR(mediumseagreen, NS_RGB(60, 179, 113))
+GFX_COLOR(mediumslateblue, NS_RGB(123, 104, 238))
+GFX_COLOR(mediumspringgreen, NS_RGB(0, 250, 154))
+GFX_COLOR(mediumturquoise, NS_RGB(72, 209, 204))
+GFX_COLOR(mediumvioletred, NS_RGB(199, 21, 133))
+GFX_COLOR(midnightblue, NS_RGB(25, 25, 112))
+GFX_COLOR(mintcream, NS_RGB(245, 255, 250))
+GFX_COLOR(mistyrose, NS_RGB(255, 228, 225))
+GFX_COLOR(moccasin, NS_RGB(255, 228, 181))
+GFX_COLOR(navajowhite, NS_RGB(255, 222, 173))
+GFX_COLOR(navy, NS_RGB(0, 0, 128))
+GFX_COLOR(oldlace, NS_RGB(253, 245, 230))
+GFX_COLOR(olive, NS_RGB(128, 128, 0))
+GFX_COLOR(olivedrab, NS_RGB(107, 142, 35))
+GFX_COLOR(orange, NS_RGB(255, 165, 0))
+GFX_COLOR(orangered, NS_RGB(255, 69, 0))
+GFX_COLOR(orchid, NS_RGB(218, 112, 214))
+GFX_COLOR(palegoldenrod, NS_RGB(238, 232, 170))
+GFX_COLOR(palegreen, NS_RGB(152, 251, 152))
+GFX_COLOR(paleturquoise, NS_RGB(175, 238, 238))
+GFX_COLOR(palevioletred, NS_RGB(219, 112, 147))
+GFX_COLOR(papayawhip, NS_RGB(255, 239, 213))
+GFX_COLOR(peachpuff, NS_RGB(255, 218, 185))
+GFX_COLOR(peru, NS_RGB(205, 133, 63))
+GFX_COLOR(pink, NS_RGB(255, 192, 203))
+GFX_COLOR(plum, NS_RGB(221, 160, 221))
+GFX_COLOR(powderblue, NS_RGB(176, 224, 230))
+GFX_COLOR(purple, NS_RGB(128, 0, 128))
+GFX_COLOR(rebeccapurple, NS_RGB(102, 51, 153))
+GFX_COLOR(red, NS_RGB(255, 0, 0))
+GFX_COLOR(rosybrown, NS_RGB(188, 143, 143))
+GFX_COLOR(royalblue, NS_RGB(65, 105, 225))
+GFX_COLOR(saddlebrown, NS_RGB(139, 69, 19))
+GFX_COLOR(salmon, NS_RGB(250, 128, 114))
+GFX_COLOR(sandybrown, NS_RGB(244, 164, 96))
+GFX_COLOR(seagreen, NS_RGB(46, 139, 87))
+GFX_COLOR(seashell, NS_RGB(255, 245, 238))
+GFX_COLOR(sienna, NS_RGB(160, 82, 45))
+GFX_COLOR(silver, NS_RGB(192, 192, 192))
+GFX_COLOR(skyblue, NS_RGB(135, 206, 235))
+GFX_COLOR(slateblue, NS_RGB(106, 90, 205))
+GFX_COLOR(slategray, NS_RGB(112, 128, 144))
+GFX_COLOR(slategrey, NS_RGB(112, 128, 144))
+GFX_COLOR(snow, NS_RGB(255, 250, 250))
+GFX_COLOR(springgreen, NS_RGB(0, 255, 127))
+GFX_COLOR(steelblue, NS_RGB(70, 130, 180))
+GFX_COLOR(tan, NS_RGB(210, 180, 140))
+GFX_COLOR(teal, NS_RGB(0, 128, 128))
+GFX_COLOR(thistle, NS_RGB(216, 191, 216))
+GFX_COLOR(tomato, NS_RGB(255, 99, 71))
+GFX_COLOR(transparent, NS_RGBA(0, 0, 0, 0))
+GFX_COLOR(turquoise, NS_RGB(64, 224, 208))
+GFX_COLOR(violet, NS_RGB(238, 130, 238))
+GFX_COLOR(wheat, NS_RGB(245, 222, 179))
+GFX_COLOR(white, NS_RGB(255, 255, 255))
+GFX_COLOR(whitesmoke, NS_RGB(245, 245, 245))
+GFX_COLOR(yellow, NS_RGB(255, 255, 0))
+GFX_COLOR(yellowgreen, NS_RGB(154, 205, 50))
diff --git a/gfx/src/nsColorNames.h b/gfx/src/nsColorNames.h
new file mode 100644
index 0000000000..d30ec751aa
--- /dev/null
+++ b/gfx/src/nsColorNames.h
@@ -0,0 +1,16 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsColorNames_h___
+#define nsColorNames_h___
+
+class nsColorNames {
+ public:
+  static void AddRefTable(void);
+  static void ReleaseTable(void);
+};
+
+#endif /* nsColorNames_h___ */
diff --git a/gfx/src/nsCoord.h b/gfx/src/nsCoord.h
new file mode 100644
index 0000000000..9d2241f15a
--- /dev/null
+++ b/gfx/src/nsCoord.h
@@ -0,0 +1,386 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSCOORD_H
+#define NSCOORD_H
+
+#include <algorithm>
+#include <cstdint>
+#include <cstdlib>
+#include <math.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/gfx/Coord.h"
+#include "nsMathUtils.h"
+
+/*
+ * Basic type used for the geometry classes.
+ *
+ * Normally all coordinates are maintained in an app unit coordinate
+ * space. An app unit is 1/60th of a CSS device pixel, which is, in turn
+ * an integer number of device pixels, such at the CSS DPI is as close to
+ * 96dpi as possible.
+ */
+
+typedef int32_t nscoord;
+#define nscoord_MAX nscoord((1 << 30) - 1)
+#define nscoord_MIN (-nscoord_MAX)
+
+namespace mozilla {
+struct AppUnit {};
+
+// Declare AppUnit as a coordinate system tag.
+template <>
+struct IsPixel<AppUnit> : std::true_type {};
+
+namespace detail {
+template <typename Rep>
+struct AuCoordImpl : public gfx::IntCoordTyped<AppUnit, Rep> {
+  using Super = gfx::IntCoordTyped<AppUnit, Rep>;
+
+  constexpr AuCoordImpl() : Super() {}
+  constexpr MOZ_IMPLICIT AuCoordImpl(Rep aValue) : Super(aValue) {}
+  constexpr MOZ_IMPLICIT AuCoordImpl(Super aValue) : Super(aValue) {}
+
+  template <typename F>
+  static AuCoordImpl FromRound(F aValue) {
+    // Note: aValue is *not* rounding to nearest integer if it is negative. See
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=410748#c14
+    return AuCoordImpl(std::floor(aValue + 0.5f));
+  }
+
+  template <typename F>
+  static AuCoordImpl FromTruncate(F aValue) {
+    return AuCoordImpl(std::trunc(aValue));
+  }
+
+  template <typename F>
+  static AuCoordImpl FromCeil(F aValue) {
+    return AuCoordImpl(std::ceil(aValue));
+  }
+
+  template <typename F>
+  static AuCoordImpl FromFloor(F aValue) {
+    return AuCoordImpl(std::floor(aValue));
+  }
+
+  // Note: this returns the result of the operation, without modifying the
+  // original value.
+  [[nodiscard]] AuCoordImpl ToMinMaxClamped() const {
+    return std::clamp(this->value, kMin, kMax);
+  }
+
+  static constexpr Rep kMax = nscoord_MAX;
+  static constexpr Rep kMin = nscoord_MIN;
+};
+}  // namespace detail
+
+using AuCoord = detail::AuCoordImpl<int32_t>;
+using AuCoord64 = detail::AuCoordImpl<int64_t>;
+
+}  // namespace mozilla
+
+/**
+ * Divide aSpace by aN.  Assign the resulting quotient to aQuotient and
+ * return the remainder.
+ */
+inline nscoord NSCoordDivRem(nscoord aSpace, size_t aN, nscoord* aQuotient) {
+  div_t result = div(aSpace, aN);
+  *aQuotient = nscoord(result.quot);
+  return nscoord(result.rem);
+}
+
+inline nscoord NSCoordMulDiv(nscoord aMult1, nscoord aMult2, nscoord aDiv) {
+  return (int64_t(aMult1) * int64_t(aMult2) / int64_t(aDiv));
+}
+
+inline nscoord NSToCoordRound(float aValue) {
+#if defined(XP_WIN) && defined(_M_IX86) && !defined(__GNUC__) && \
+    !defined(__clang__)
+  return NS_lroundup30(aValue);
+#else
+  return nscoord(floorf(aValue + 0.5f));
+#endif /* XP_WIN && _M_IX86 && !__GNUC__ */
+}
+
+inline nscoord NSToCoordRound(double aValue) {
+#if defined(XP_WIN) && defined(_M_IX86) && !defined(__GNUC__) && \
+    !defined(__clang__)
+  return NS_lroundup30((float)aValue);
+#else
+  return nscoord(floor(aValue + 0.5f));
+#endif /* XP_WIN && _M_IX86 && !__GNUC__ */
+}
+
+inline nscoord NSToCoordRoundWithClamp(float aValue) {
+  // Bounds-check before converting out of float, to avoid overflow
+  if (aValue >= float(nscoord_MAX)) {
+    return nscoord_MAX;
+  }
+  if (aValue <= float(nscoord_MIN)) {
+    return nscoord_MIN;
+  }
+  return NSToCoordRound(aValue);
+}
+
+inline nscoord NSToCoordRoundWithClamp(double aValue) {
+  // Bounds-check before converting out of double, to avoid overflow
+  if (aValue >= double(nscoord_MAX)) {
+    return nscoord_MAX;
+  }
+  if (aValue <= double(nscoord_MIN)) {
+    return nscoord_MIN;
+  }
+  return NSToCoordRound(aValue);
+}
+
+/**
+ * Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as
+ * appropriate for the signs of aCoord and aScale.  If requireNotNegative is
+ * true, this method will enforce that aScale is not negative; use that
+ * parametrization to get a check of that fact in debug builds.
+ */
+inline nscoord _nscoordSaturatingMultiply(nscoord aCoord, float aScale,
+                                          bool requireNotNegative) {
+  if (requireNotNegative) {
+    MOZ_ASSERT(aScale >= 0.0f,
+               "negative scaling factors must be handled manually");
+  }
+  float product = aCoord * aScale;
+  if (requireNotNegative ? aCoord > 0 : (aCoord > 0) == (aScale > 0))
+    return NSToCoordRoundWithClamp(
+        std::min<float>((float)nscoord_MAX, product));
+  return NSToCoordRoundWithClamp(std::max<float>((float)nscoord_MIN, product));
+}
+
+/**
+ * Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as
+ * appropriate for the sign of aCoord.  This method requires aScale to not be
+ * negative; use this method when you know that aScale should never be
+ * negative to get a sanity check of that invariant in debug builds.
+ */
+inline nscoord NSCoordSaturatingNonnegativeMultiply(nscoord aCoord,
+                                                    float aScale) {
+  return _nscoordSaturatingMultiply(aCoord, aScale, true);
+}
+
+/**
+ * Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as
+ * appropriate for the signs of aCoord and aScale.
+ */
+inline nscoord NSCoordSaturatingMultiply(nscoord aCoord, float aScale) {
+  return _nscoordSaturatingMultiply(aCoord, aScale, false);
+}
+
+/**
+ * Returns a + b, capping the sum to nscoord_MAX.
+ *
+ * This function assumes that neither argument is nscoord_MIN.
+ */
+inline nscoord NSCoordSaturatingAdd(nscoord a, nscoord b) {
+  if (a == nscoord_MAX || b == nscoord_MAX) {
+    // infinity + anything = anything + infinity = infinity
+    return nscoord_MAX;
+  } else {
+    // a + b = a + b
+    // Cap the result, just in case we're dealing with numbers near nscoord_MAX
+    return std::min(nscoord_MAX, a + b);
+  }
+}
+
+/**
+ * Returns a - b, gracefully handling cases involving nscoord_MAX.
+ * This function assumes that neither argument is nscoord_MIN.
+ *
+ * The behavior is as follows:
+ *
+ *  a)  infinity - infinity -> infMinusInfResult
+ *  b)  N - infinity        -> 0  (unexpected -- triggers NOTREACHED)
+ *  c)  infinity - N        -> infinity
+ *  d)  N1 - N2             -> N1 - N2
+ */
+inline nscoord NSCoordSaturatingSubtract(nscoord a, nscoord b,
+                                         nscoord infMinusInfResult) {
+  if (b == nscoord_MAX) {
+    if (a == nscoord_MAX) {
+      // case (a)
+      return infMinusInfResult;
+    } else {
+      // case (b)
+      return 0;
+    }
+  } else {
+    if (a == nscoord_MAX) {
+      // case (c) for integers
+      return nscoord_MAX;
+    } else {
+      // case (d) for integers
+      // Cap the result, in case we're dealing with numbers near nscoord_MAX
+      return std::min(nscoord_MAX, a - b);
+    }
+  }
+}
+
+inline float NSCoordToFloat(nscoord aCoord) { return (float)aCoord; }
+
+/*
+ * Coord Rounding Functions
+ */
+inline nscoord NSToCoordFloor(float aValue) { return nscoord(floorf(aValue)); }
+
+inline nscoord NSToCoordFloor(double aValue) { return nscoord(floor(aValue)); }
+
+inline nscoord NSToCoordFloorClamped(float aValue) {
+  // Bounds-check before converting out of float, to avoid overflow
+  if (aValue >= float(nscoord_MAX)) {
+    return nscoord_MAX;
+  }
+  if (aValue <= float(nscoord_MIN)) {
+    return nscoord_MIN;
+  }
+  return NSToCoordFloor(aValue);
+}
+
+inline nscoord NSToCoordCeil(float aValue) { return nscoord(ceilf(aValue)); }
+
+inline nscoord NSToCoordCeil(double aValue) { return nscoord(ceil(aValue)); }
+
+inline nscoord NSToCoordCeilClamped(double aValue) {
+  // Bounds-check before converting out of double, to avoid overflow
+  if (aValue >= nscoord_MAX) {
+    return nscoord_MAX;
+  }
+  if (aValue <= nscoord_MIN) {
+    return nscoord_MIN;
+  }
+  return NSToCoordCeil(aValue);
+}
+
+// The NSToCoordTrunc* functions remove the fractional component of
+// aValue, and are thus equivalent to NSToCoordFloor* for positive
+// values and NSToCoordCeil* for negative values.
+
+inline nscoord NSToCoordTrunc(float aValue) {
+  // There's no need to use truncf() since it matches the default
+  // rules for float to integer conversion.
+  return nscoord(aValue);
+}
+
+inline nscoord NSToCoordTrunc(double aValue) {
+  // There's no need to use trunc() since it matches the default
+  // rules for float to integer conversion.
+  return nscoord(aValue);
+}
+
+inline nscoord NSToCoordTruncClamped(float aValue) {
+  // Bounds-check before converting out of float, to avoid overflow
+  if (aValue >= float(nscoord_MAX)) {
+    return nscoord_MAX;
+  }
+  if (aValue <= float(nscoord_MIN)) {
+    return nscoord_MIN;
+  }
+  return NSToCoordTrunc(aValue);
+}
+
+inline nscoord NSToCoordTruncClamped(double aValue) {
+  // Bounds-check before converting out of double, to avoid overflow
+  if (aValue >= float(nscoord_MAX)) {
+    return nscoord_MAX;
+  }
+  if (aValue <= float(nscoord_MIN)) {
+    return nscoord_MIN;
+  }
+  return NSToCoordTrunc(aValue);
+}
+
+/*
+ * Int Rounding Functions
+ */
+inline int32_t NSToIntFloor(float aValue) { return int32_t(floorf(aValue)); }
+
+inline int32_t NSToIntCeil(float aValue) { return int32_t(ceilf(aValue)); }
+
+inline int32_t NSToIntRound(float aValue) { return NS_lroundf(aValue); }
+
+inline int32_t NSToIntRound(double aValue) { return NS_lround(aValue); }
+
+inline int32_t NSToIntRoundUp(double aValue) {
+  return int32_t(floor(aValue + 0.5));
+}
+
+/*
+ * App Unit/Pixel conversions
+ */
+inline nscoord NSFloatPixelsToAppUnits(float aPixels, float aAppUnitsPerPixel) {
+  return NSToCoordRoundWithClamp(aPixels * aAppUnitsPerPixel);
+}
+
+inline nscoord NSIntPixelsToAppUnits(int32_t aPixels,
+                                     int32_t aAppUnitsPerPixel) {
+  // The cast to nscoord makes sure we don't overflow if we ever change
+  // nscoord to float
+  nscoord r = aPixels * (nscoord)aAppUnitsPerPixel;
+  return r;
+}
+
+inline float NSAppUnitsToFloatPixels(nscoord aAppUnits,
+                                     float aAppUnitsPerPixel) {
+  return (float(aAppUnits) / aAppUnitsPerPixel);
+}
+
+inline double NSAppUnitsToDoublePixels(nscoord aAppUnits,
+                                       double aAppUnitsPerPixel) {
+  return (double(aAppUnits) / aAppUnitsPerPixel);
+}
+
+inline int32_t NSAppUnitsToIntPixels(nscoord aAppUnits,
+                                     float aAppUnitsPerPixel) {
+  return NSToIntRound(float(aAppUnits) / aAppUnitsPerPixel);
+}
+
+inline float NSCoordScale(nscoord aCoord, int32_t aFromAPP, int32_t aToAPP) {
+  return (NSCoordToFloat(aCoord) * aToAPP) / aFromAPP;
+}
+
+/// handy constants
+#define TWIPS_PER_POINT_INT 20
+#define TWIPS_PER_POINT_FLOAT 20.0f
+#define POINTS_PER_INCH_INT 72
+#define POINTS_PER_INCH_FLOAT 72.0f
+#define CM_PER_INCH_FLOAT 2.54f
+#define MM_PER_INCH_FLOAT 25.4f
+
+/*
+ * Twips/unit conversions
+ */
+inline float NSUnitsToTwips(float aValue, float aPointsPerUnit) {
+  return aValue * aPointsPerUnit * TWIPS_PER_POINT_FLOAT;
+}
+
+inline float NSTwipsToUnits(float aTwips, float aUnitsPerPoint) {
+  return (aTwips * (aUnitsPerPoint / TWIPS_PER_POINT_FLOAT));
+}
+
+/// Unit conversion macros
+//@{
+#define NS_POINTS_TO_TWIPS(x) NSUnitsToTwips((x), 1.0f)
+#define NS_INCHES_TO_TWIPS(x) \
+  NSUnitsToTwips((x), POINTS_PER_INCH_FLOAT)  // 72 points per inch
+
+#define NS_MILLIMETERS_TO_TWIPS(x) \
+  NSUnitsToTwips((x), (POINTS_PER_INCH_FLOAT * 0.03937f))
+
+#define NS_POINTS_TO_INT_TWIPS(x) NSToIntRound(NS_POINTS_TO_TWIPS(x))
+#define NS_INCHES_TO_INT_TWIPS(x) NSToIntRound(NS_INCHES_TO_TWIPS(x))
+
+#define NS_TWIPS_TO_INCHES(x) NSTwipsToUnits((x), 1.0f / POINTS_PER_INCH_FLOAT)
+
+#define NS_TWIPS_TO_MILLIMETERS(x) \
+  NSTwipsToUnits((x), 1.0f / (POINTS_PER_INCH_FLOAT * 0.03937f))
+//@}
+
+#endif /* NSCOORD_H */
diff --git a/gfx/src/nsDeviceContext.cpp b/gfx/src/nsDeviceContext.cpp
new file mode 100644
index 0000000000..f9fba58418
--- /dev/null
+++ b/gfx/src/nsDeviceContext.cpp
@@ -0,0 +1,458 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=2 expandtab: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDeviceContext.h"
+#include <algorithm>  // for max
+#include "gfxContext.h"
+#include "gfxImageSurface.h"  // for gfxImageSurface
+#include "gfxPoint.h"         // for gfxSize
+#include "gfxTextRun.h"       // for gfxFontGroup
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/gfx/PathHelpers.h"
+#include "mozilla/gfx/PrintTarget.h"
+#include "mozilla/Preferences.h"  // for Preferences
+#include "mozilla/Services.h"     // for GetObserverService
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/mozalloc.h"       // for operator new
+#include "mozilla/widget/Screen.h"  // for Screen
+#include "nsCRT.h"                  // for nsCRT
+#include "nsDebug.h"                // for NS_ASSERTION, etc
+#include "nsFont.h"                 // for nsFont
+#include "nsFontCache.h"            // for nsFontCache
+#include "nsFontMetrics.h"          // for nsFontMetrics
+#include "nsAtom.h"                 // for nsAtom, NS_Atomize
+#include "nsID.h"
+#include "nsIDeviceContextSpec.h"   // for nsIDeviceContextSpec
+#include "nsLanguageAtomService.h"  // for nsLanguageAtomService
+#include "nsIObserver.h"            // for nsIObserver, etc
+#include "nsIObserverService.h"     // for nsIObserverService
+#include "nsISupportsImpl.h"        // for MOZ_COUNT_CTOR, etc
+#include "nsISupportsUtils.h"       // for NS_ADDREF, NS_RELEASE
+#include "nsIWidget.h"              // for nsIWidget, NS_NATIVE_WINDOW
+#include "nsRect.h"                 // for nsRect
+#include "nsServiceManagerUtils.h"  // for do_GetService
+#include "nsString.h"               // for nsDependentString
+#include "nsTArray.h"               // for nsTArray, nsTArray_Impl
+#include "nsThreadUtils.h"          // for NS_IsMainThread
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/widget/ScreenManager.h"  // for ScreenManager
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using mozilla::widget::ScreenManager;
+
+nsDeviceContext::nsDeviceContext()
+    : mWidth(0),
+      mHeight(0),
+      mAppUnitsPerDevPixel(-1),
+      mAppUnitsPerDevPixelAtUnitFullZoom(-1),
+      mAppUnitsPerPhysicalInch(-1),
+      mFullZoom(1.0f),
+      mPrintingScale(1.0f),
+      mPrintingTranslate(gfxPoint(0, 0)),
+      mIsCurrentlyPrintingDoc(false) {
+  MOZ_ASSERT(NS_IsMainThread(), "nsDeviceContext created off main thread");
+}
+
+nsDeviceContext::~nsDeviceContext() = default;
+
+void nsDeviceContext::SetDPI() {
+  float dpi;
+
+  // Use the printing DC to determine DPI values, if we have one.
+  if (mDeviceContextSpec) {
+    dpi = mDeviceContextSpec->GetDPI();
+    mPrintingScale = mDeviceContextSpec->GetPrintingScale();
+    mPrintingTranslate = mDeviceContextSpec->GetPrintingTranslate();
+    mAppUnitsPerDevPixelAtUnitFullZoom =
+        NS_lround((AppUnitsPerCSSPixel() * 96) / dpi);
+  } else {
+    // A value of -1 means use the maximum of 96 and the system DPI.
+    // A value of 0 means use the system DPI. A positive value is used as the
+    // DPI. This sets the physical size of a device pixel and thus controls the
+    // interpretation of physical units.
+    int32_t prefDPI = StaticPrefs::layout_css_dpi();
+    if (prefDPI > 0) {
+      dpi = prefDPI;
+    } else if (mWidget) {
+      dpi = mWidget->GetDPI();
+      MOZ_ASSERT(dpi > 0);
+      if (prefDPI < 0) {
+        dpi = std::max(96.0f, dpi);
+      }
+    } else {
+      dpi = 96.0f;
+    }
+
+    CSSToLayoutDeviceScale scale =
+        mWidget ? mWidget->GetDefaultScale() : CSSToLayoutDeviceScale(1.0);
+    MOZ_ASSERT(scale.scale > 0.0);
+    mAppUnitsPerDevPixelAtUnitFullZoom =
+        std::max(1, NS_lround(AppUnitsPerCSSPixel() / scale.scale));
+  }
+
+  NS_ASSERTION(dpi != -1.0, "no dpi set");
+
+  mAppUnitsPerPhysicalInch =
+      NS_lround(dpi * mAppUnitsPerDevPixelAtUnitFullZoom);
+  UpdateAppUnitsForFullZoom();
+}
+
+void nsDeviceContext::Init(nsIWidget* aWidget) {
+  if (mIsInitialized && mWidget == aWidget) {
+    return;
+  }
+
+  // We can't assert |!mIsInitialized| here since EndSwapDocShellsForDocument
+  // re-initializes nsDeviceContext objects.  We can only assert in
+  // InitForPrinting (below).
+  mIsInitialized = true;
+
+  mWidget = aWidget;
+  SetDPI();
+}
+
+// XXX This is only for printing. We should make that obvious in the name.
+UniquePtr<gfxContext> nsDeviceContext::CreateRenderingContext() {
+  return CreateRenderingContextCommon(/* not a reference context */ false);
+}
+
+UniquePtr<gfxContext> nsDeviceContext::CreateReferenceRenderingContext() {
+  return CreateRenderingContextCommon(/* a reference context */ true);
+}
+
+UniquePtr<gfxContext> nsDeviceContext::CreateRenderingContextCommon(
+    bool aWantReferenceContext) {
+  MOZ_ASSERT(IsPrinterContext());
+  MOZ_ASSERT(mWidth > 0 && mHeight > 0);
+
+  if (NS_WARN_IF(!mPrintTarget)) {
+    // Printing canceled already.
+    return nullptr;
+  }
+
+  RefPtr<gfx::DrawTarget> dt;
+  if (aWantReferenceContext) {
+    dt = mPrintTarget->GetReferenceDrawTarget();
+  } else {
+    // This will be null if printing a page from the parent process.
+    RefPtr<DrawEventRecorder> recorder;
+    mDeviceContextSpec->GetDrawEventRecorder(getter_AddRefs(recorder));
+    dt = mPrintTarget->MakeDrawTarget(gfx::IntSize(mWidth, mHeight), recorder);
+  }
+
+  if (!dt || !dt->IsValid()) {
+    gfxCriticalNote << "Failed to create draw target in device context sized "
+                    << mWidth << "x" << mHeight << " and pointer "
+                    << hexa(mPrintTarget);
+    return nullptr;
+  }
+
+  dt->AddUserData(&sDisablePixelSnapping, (void*)0x1, nullptr);
+
+  auto pContext = MakeUnique<gfxContext>(dt);
+
+  gfxMatrix transform;
+  transform.PreTranslate(mPrintingTranslate);
+  transform.PreScale(mPrintingScale, mPrintingScale);
+  pContext->SetMatrixDouble(transform);
+  return pContext;
+}
+
+uint32_t nsDeviceContext::GetDepth() {
+  RefPtr<widget::Screen> screen = FindScreen();
+  if (!screen) {
+    ScreenManager& screenManager = ScreenManager::GetSingleton();
+    screen = screenManager.GetPrimaryScreen();
+    MOZ_ASSERT(screen);
+  }
+  int32_t depth = 0;
+  screen->GetColorDepth(&depth);
+  return uint32_t(depth);
+}
+
+dom::ScreenColorGamut nsDeviceContext::GetColorGamut() {
+  RefPtr<widget::Screen> screen = FindScreen();
+  if (!screen) {
+    auto& screenManager = ScreenManager::GetSingleton();
+    screen = screenManager.GetPrimaryScreen();
+    MOZ_ASSERT(screen);
+  }
+  dom::ScreenColorGamut colorGamut;
+  screen->GetColorGamut(&colorGamut);
+  return colorGamut;
+}
+
+hal::ScreenOrientation nsDeviceContext::GetScreenOrientationType() {
+  RefPtr<widget::Screen> screen = FindScreen();
+  if (!screen) {
+    auto& screenManager = ScreenManager::GetSingleton();
+    screen = screenManager.GetPrimaryScreen();
+    MOZ_ASSERT(screen);
+  }
+  return screen->GetOrientationType();
+}
+
+uint16_t nsDeviceContext::GetScreenOrientationAngle() {
+  RefPtr<widget::Screen> screen = FindScreen();
+  if (!screen) {
+    auto& screenManager = ScreenManager::GetSingleton();
+    screen = screenManager.GetPrimaryScreen();
+    MOZ_ASSERT(screen);
+  }
+  return screen->GetOrientationAngle();
+}
+
+nsresult nsDeviceContext::GetDeviceSurfaceDimensions(nscoord& aWidth,
+                                                     nscoord& aHeight) {
+  if (IsPrinterContext()) {
+    aWidth = mWidth;
+    aHeight = mHeight;
+  } else {
+    nsRect area;
+    ComputeFullAreaUsingScreen(&area);
+    aWidth = area.Width();
+    aHeight = area.Height();
+  }
+
+  return NS_OK;
+}
+
+nsresult nsDeviceContext::GetRect(nsRect& aRect) {
+  if (IsPrinterContext()) {
+    aRect.SetRect(0, 0, mWidth, mHeight);
+  } else
+    ComputeFullAreaUsingScreen(&aRect);
+
+  return NS_OK;
+}
+
+nsresult nsDeviceContext::GetClientRect(nsRect& aRect) {
+  if (IsPrinterContext()) {
+    aRect.SetRect(0, 0, mWidth, mHeight);
+  } else
+    ComputeClientRectUsingScreen(&aRect);
+
+  return NS_OK;
+}
+
+nsresult nsDeviceContext::InitForPrinting(nsIDeviceContextSpec* aDevice) {
+  NS_ENSURE_ARG_POINTER(aDevice);
+
+  MOZ_ASSERT(!mIsInitialized,
+             "Only initialize once, immediately after construction");
+
+  // We don't set mIsInitialized here. The Init() call below does that.
+
+  mPrintTarget = aDevice->MakePrintTarget();
+  if (!mPrintTarget) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mDeviceContextSpec = aDevice;
+
+  Init(nullptr);
+
+  if (!CalcPrintingSize()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+nsresult nsDeviceContext::BeginDocument(const nsAString& aTitle,
+                                        const nsAString& aPrintToFileName,
+                                        int32_t aStartPage, int32_t aEndPage) {
+  MOZ_DIAGNOSTIC_ASSERT(!mIsCurrentlyPrintingDoc,
+                        "Mismatched BeginDocument/EndDocument calls");
+
+  nsresult rv = mPrintTarget->BeginPrinting(aTitle, aPrintToFileName,
+                                            aStartPage, aEndPage);
+
+  if (NS_SUCCEEDED(rv)) {
+    if (mDeviceContextSpec) {
+      rv = mDeviceContextSpec->BeginDocument(aTitle, aPrintToFileName,
+                                             aStartPage, aEndPage);
+    }
+    mIsCurrentlyPrintingDoc = true;
+  }
+
+  // Warn about any failure (except user cancelling):
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv) || rv == NS_ERROR_ABORT,
+                       "nsDeviceContext::BeginDocument failed");
+
+  return rv;
+}
+
+RefPtr<PrintEndDocumentPromise> nsDeviceContext::EndDocument() {
+  MOZ_DIAGNOSTIC_ASSERT(mIsCurrentlyPrintingDoc,
+                        "Mismatched BeginDocument/EndDocument calls");
+  MOZ_DIAGNOSTIC_ASSERT(mPrintTarget);
+
+  mIsCurrentlyPrintingDoc = false;
+
+  if (mPrintTarget) {
+    auto result = mPrintTarget->EndPrinting();
+    if (NS_FAILED(result)) {
+      return PrintEndDocumentPromise::CreateAndReject(NS_ERROR_NOT_AVAILABLE,
+                                                      __func__);
+    }
+    mPrintTarget->Finish();
+    mPrintTarget = nullptr;
+  }
+
+  if (mDeviceContextSpec) {
+    return mDeviceContextSpec->EndDocument();
+  }
+
+  return PrintEndDocumentPromise::CreateAndResolve(true, __func__);
+}
+
+nsresult nsDeviceContext::AbortDocument() {
+  MOZ_DIAGNOSTIC_ASSERT(mIsCurrentlyPrintingDoc,
+                        "Mismatched BeginDocument/EndDocument calls");
+
+  nsresult rv = mPrintTarget->AbortPrinting();
+  mIsCurrentlyPrintingDoc = false;
+
+  if (mDeviceContextSpec) {
+    Unused << mDeviceContextSpec->EndDocument();
+  }
+
+  mPrintTarget = nullptr;
+
+  return rv;
+}
+
+nsresult nsDeviceContext::BeginPage() {
+  MOZ_DIAGNOSTIC_ASSERT(!mIsCurrentlyPrintingDoc || mPrintTarget,
+                        "What nulled out our print target while printing?");
+  if (mDeviceContextSpec) {
+    MOZ_TRY(mDeviceContextSpec->BeginPage());
+  }
+  if (mPrintTarget) {
+    MOZ_TRY(mPrintTarget->BeginPage());
+  }
+  return NS_OK;
+}
+
+nsresult nsDeviceContext::EndPage() {
+  MOZ_DIAGNOSTIC_ASSERT(!mIsCurrentlyPrintingDoc || mPrintTarget,
+                        "What nulled out our print target while printing?");
+  if (mPrintTarget) {
+    MOZ_TRY(mPrintTarget->EndPage());
+  }
+  if (mDeviceContextSpec) {
+    MOZ_TRY(mDeviceContextSpec->EndPage());
+  }
+  return NS_OK;
+}
+
+void nsDeviceContext::ComputeClientRectUsingScreen(nsRect* outRect) {
+  // we always need to recompute the clientRect
+  // because the window may have moved onto a different screen. In the single
+  // monitor case, we only need to do the computation if we haven't done it
+  // once already, and remember that we have because we're assured it won't
+  // change.
+  if (RefPtr<widget::Screen> screen = FindScreen()) {
+    *outRect = LayoutDeviceIntRect::ToAppUnits(screen->GetAvailRect(),
+                                               AppUnitsPerDevPixel());
+  }
+}
+
+void nsDeviceContext::ComputeFullAreaUsingScreen(nsRect* outRect) {
+  // if we have more than one screen, we always need to recompute the clientRect
+  // because the window may have moved onto a different screen. In the single
+  // monitor case, we only need to do the computation if we haven't done it
+  // once already, and remember that we have because we're assured it won't
+  // change.
+  if (RefPtr<widget::Screen> screen = FindScreen()) {
+    *outRect = LayoutDeviceIntRect::ToAppUnits(screen->GetRect(),
+                                               AppUnitsPerDevPixel());
+    mWidth = outRect->Width();
+    mHeight = outRect->Height();
+  }
+}
+
+//
+// FindScreen
+//
+// Determines which screen intersects the largest area of the given surface.
+//
+already_AddRefed<widget::Screen> nsDeviceContext::FindScreen() {
+  if (!mWidget) {
+    return nullptr;
+  }
+
+  CheckDPIChange();
+
+  if (RefPtr<widget::Screen> screen = mWidget->GetWidgetScreen()) {
+    return screen.forget();
+  }
+
+  ScreenManager& screenManager = ScreenManager::GetSingleton();
+  return screenManager.GetPrimaryScreen();
+}
+
+bool nsDeviceContext::CalcPrintingSize() {
+  gfxSize size(mPrintTarget->GetSize());
+  // For printing, CSS inches and physical inches are identical
+  // so it doesn't matter which we use here
+  mWidth = NSToCoordRound(size.width * AppUnitsPerPhysicalInch() /
+                          POINTS_PER_INCH_FLOAT);
+  mHeight = NSToCoordRound(size.height * AppUnitsPerPhysicalInch() /
+                           POINTS_PER_INCH_FLOAT);
+
+  return (mWidth > 0 && mHeight > 0);
+}
+
+bool nsDeviceContext::CheckDPIChange() {
+  int32_t oldDevPixels = mAppUnitsPerDevPixelAtUnitFullZoom;
+  int32_t oldInches = mAppUnitsPerPhysicalInch;
+
+  SetDPI();
+
+  return oldDevPixels != mAppUnitsPerDevPixelAtUnitFullZoom ||
+         oldInches != mAppUnitsPerPhysicalInch;
+}
+
+bool nsDeviceContext::SetFullZoom(float aScale) {
+  if (aScale <= 0) {
+    MOZ_ASSERT_UNREACHABLE("Invalid full zoom value");
+    return false;
+  }
+  int32_t oldAppUnitsPerDevPixel = mAppUnitsPerDevPixel;
+  mFullZoom = aScale;
+  UpdateAppUnitsForFullZoom();
+  return oldAppUnitsPerDevPixel != mAppUnitsPerDevPixel;
+}
+
+static int32_t ApplyFullZoom(int32_t aUnzoomedAppUnits, float aFullZoom) {
+  if (aFullZoom == 1.0f) {
+    return aUnzoomedAppUnits;
+  }
+  return std::max(1, NSToIntRound(float(aUnzoomedAppUnits) / aFullZoom));
+}
+
+int32_t nsDeviceContext::AppUnitsPerDevPixelInTopLevelChromePage() const {
+  // The only zoom that applies to chrome pages is the system zoom, if any.
+  return ApplyFullZoom(mAppUnitsPerDevPixelAtUnitFullZoom,
+                       LookAndFeel::SystemZoomSettings().mFullZoom);
+}
+
+void nsDeviceContext::UpdateAppUnitsForFullZoom() {
+  mAppUnitsPerDevPixel =
+      ApplyFullZoom(mAppUnitsPerDevPixelAtUnitFullZoom, mFullZoom);
+  // adjust mFullZoom to reflect appunit rounding
+  mFullZoom = float(mAppUnitsPerDevPixelAtUnitFullZoom) / mAppUnitsPerDevPixel;
+}
+
+DesktopToLayoutDeviceScale nsDeviceContext::GetDesktopToDeviceScale() {
+  if (RefPtr<widget::Screen> screen = FindScreen()) {
+    return screen->GetDesktopToLayoutDeviceScale();
+  }
+  return DesktopToLayoutDeviceScale(1.0);
+}
diff --git a/gfx/src/nsDeviceContext.h b/gfx/src/nsDeviceContext.h
new file mode 100644
index 0000000000..8ebb240650
--- /dev/null
+++ b/gfx/src/nsDeviceContext.h
@@ -0,0 +1,301 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _NS_DEVICECONTEXT_H_
+#define _NS_DEVICECONTEXT_H_
+
+#include <stdint.h>                   // for uint32_t
+#include <sys/types.h>                // for int32_t
+#include "gfxTypes.h"                 // for gfxFloat
+#include "gfxFont.h"                  // for gfxFont::Orientation
+#include "mozilla/Assertions.h"       // for MOZ_ASSERT_HELPER2
+#include "mozilla/RefPtr.h"           // for RefPtr
+#include "nsCOMPtr.h"                 // for nsCOMPtr
+#include "nsCoord.h"                  // for nscoord
+#include "nsError.h"                  // for nsresult
+#include "nsISupports.h"              // for NS_INLINE_DECL_REFCOUNTING
+#include "nsMathUtils.h"              // for NS_round
+#include "nscore.h"                   // for char16_t, nsAString
+#include "mozilla/AppUnits.h"         // for AppUnits
+#include "nsFontMetrics.h"            // for nsFontMetrics::Params
+#include "mozilla/gfx/PrintTarget.h"  // for PrintTarget::PageDoneCallback
+#include "mozilla/gfx/PrintPromise.h"
+
+class gfxContext;
+class gfxTextPerfMetrics;
+class gfxUserFontSet;
+struct nsFont;
+class nsAtom;
+class nsIDeviceContextSpec;
+class nsIScreen;
+class nsIScreenManager;
+class nsIWidget;
+struct nsRect;
+
+namespace mozilla {
+namespace dom {
+enum class ScreenColorGamut : uint8_t;
+}  // namespace dom
+namespace hal {
+enum class ScreenOrientation : uint32_t;
+}  // namespace hal
+namespace widget {
+class Screen;
+}  // namespace widget
+}  // namespace mozilla
+
+class nsDeviceContext final {
+ public:
+  typedef mozilla::gfx::PrintTarget PrintTarget;
+
+  nsDeviceContext();
+
+  NS_INLINE_DECL_REFCOUNTING(nsDeviceContext)
+
+  /**
+   * Initialize the device context from a widget
+   * @param aWidget a widget to initialize the device context from
+   */
+  void Init(nsIWidget* aWidget);
+
+  /**
+   * Initialize the device context from a device context spec
+   * @param aDevSpec the specification of the printing device
+   * @return error status
+   */
+  nsresult InitForPrinting(nsIDeviceContextSpec* aDevSpec);
+
+  /**
+   * Create a rendering context and initialize it.  Only call this
+   * method on device contexts that were initialized for printing.
+   *
+   * @return the new rendering context (guaranteed to be non-null)
+   */
+  mozilla::UniquePtr<gfxContext> CreateRenderingContext();
+
+  /**
+   * Create a reference rendering context and initialize it.  Only call this
+   * method on device contexts that were initialized for printing.
+   *
+   * @return the new rendering context.
+   */
+  mozilla::UniquePtr<gfxContext> CreateReferenceRenderingContext();
+
+  /**
+   * Gets the number of app units in one device pixel; this number
+   * is usually a factor of AppUnitsPerCSSPixel(), although that is
+   * not guaranteed.
+   */
+  int32_t AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
+
+  /**
+   * Convert device pixels which is used for gfx/thebes to nearest
+   * (rounded) app units
+   */
+  nscoord GfxUnitsToAppUnits(gfxFloat aGfxUnits) const {
+    return nscoord(NS_round(aGfxUnits * AppUnitsPerDevPixel()));
+  }
+
+  /**
+   * Convert app units to device pixels which is used for gfx/thebes.
+   */
+  gfxFloat AppUnitsToGfxUnits(nscoord aAppUnits) const {
+    return gfxFloat(aAppUnits) / AppUnitsPerDevPixel();
+  }
+
+  /**
+   * Gets the number of app units in one physical inch; this is the
+   * device's DPI times AppUnitsPerDevPixel().
+   */
+  int32_t AppUnitsPerPhysicalInch() const { return mAppUnitsPerPhysicalInch; }
+
+  /**
+   * Get the ratio of app units to dev pixels that would be used at unit
+   * (100%) full zoom.
+   */
+  int32_t AppUnitsPerDevPixelAtUnitFullZoom() const {
+    return mAppUnitsPerDevPixelAtUnitFullZoom;
+  }
+
+  /**
+   * Get the ratio of app units to dev pixels that would be used in a top-level
+   * chrome page such as browser.xhtml.
+   */
+  int32_t AppUnitsPerDevPixelInTopLevelChromePage() const;
+
+  /**
+   * Return the bit depth of the device.
+   */
+  uint32_t GetDepth();
+
+  /**
+   * Return the color gamut of the device.
+   */
+  mozilla::dom::ScreenColorGamut GetColorGamut();
+
+  /**
+   * Return the orientation type of the device.
+   * If not screen device, return primary screen's value
+   */
+  mozilla::hal::ScreenOrientation GetScreenOrientationType();
+
+  /**
+   * Return the orientation angle of the device.
+   * If not screen device, return primary screen's value
+   */
+  uint16_t GetScreenOrientationAngle();
+
+  /**
+   * Get the size of the displayable area of the output device
+   * in app units.
+   * @param aWidth out parameter for width
+   * @param aHeight out parameter for height
+   * @return error status
+   */
+  nsresult GetDeviceSurfaceDimensions(nscoord& aWidth, nscoord& aHeight);
+
+  /**
+   * Get the size of the content area of the output device in app
+   * units.  This corresponds on a screen device, for instance, to
+   * the entire screen.
+   * @param aRect out parameter for full rect. Position (x,y) will
+   *              be (0,0) or relative to the primary monitor if
+   *              this is not the primary.
+   * @return error status
+   */
+  nsresult GetRect(nsRect& aRect);
+
+  /**
+   * Get the size of the content area of the output device in app
+   * units.  This corresponds on a screen device, for instance, to
+   * the area reported by GetDeviceSurfaceDimensions, minus the
+   * taskbar (Windows) or menubar (Macintosh).
+   * @param aRect out parameter for client rect. Position (x,y) will
+   *              be (0,0) adjusted for any upper/left non-client
+   *              space if present or relative to the primary
+   *              monitor if this is not the primary.
+   * @return error status
+   */
+  nsresult GetClientRect(nsRect& aRect);
+
+  /**
+   * Returns true if we're currently between BeginDocument() and
+   * EndDocument() calls.
+   */
+  bool IsCurrentlyPrintingDocument() const { return mIsCurrentlyPrintingDoc; }
+
+  /**
+   * Inform the output device that output of a document is beginning
+   * Used for print related device contexts. Must be matched 1:1 with
+   * EndDocument() or AbortDocument().
+   *
+   * @param aTitle - title of Document
+   * @param aPrintToFileName - name of file to print to, if empty then don't
+   *                           print to file
+   * @param aStartPage - starting page number (must be greater than zero)
+   * @param aEndPage - ending page number (must be less than or
+   * equal to number of pages)
+   *
+   * @return error status
+   */
+  nsresult BeginDocument(const nsAString& aTitle,
+                         const nsAString& aPrintToFileName, int32_t aStartPage,
+                         int32_t aEndPage);
+
+  /**
+   * Inform the output device that output of a document is ending.
+   * Used for print related device contexts. Must be matched 1:1 with
+   * BeginDocument()
+   * @return Promise that can be chained once the operation is complete.
+   */
+  RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocument();
+
+  /**
+   * Inform the output device that output of a document is being aborted.
+   * Must be matched 1:1 with BeginDocument()
+   * @return error status
+   */
+  nsresult AbortDocument();
+
+  /**
+   * Inform the output device that output of a page is beginning
+   * Used for print related device contexts. Must be matched 1:1 with
+   * EndPage() and within a BeginDocument()/EndDocument() pair.
+   * @return error status
+   */
+  nsresult BeginPage();
+
+  /**
+   * Inform the output device that output of a page is ending
+   * Used for print related device contexts. Must be matched 1:1 with
+   * BeginPage() and within a BeginDocument()/EndDocument() pair.
+   * @return error status
+   */
+  nsresult EndPage();
+
+  /**
+   * Check to see if the DPI has changed, or impose a new DPI scale value.
+   * @return whether there was actually a change in the DPI (whether
+   *         AppUnitsPerDevPixel() or AppUnitsPerPhysicalInch()
+   *         changed)
+   */
+  bool CheckDPIChange();
+
+  /**
+   * Set the full zoom factor: all lengths are multiplied by this factor
+   * when we convert them to device pixels. Returns whether the ratio of
+   * app units to dev pixels changed because of the zoom factor.
+   */
+  bool SetFullZoom(float aScale);
+
+  /**
+   * Returns the page full zoom factor applied.
+   */
+  float GetFullZoom() const { return mFullZoom; }
+
+  /**
+   * True if this device context was created for printing.
+   */
+  bool IsPrinterContext() const { return !!mPrintTarget; }
+
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale();
+
+ private:
+  // Private destructor, to discourage deletion outside of Release():
+  ~nsDeviceContext();
+
+  /**
+   * Implementation shared by CreateRenderingContext and
+   * CreateReferenceRenderingContext.
+   */
+  mozilla::UniquePtr<gfxContext> CreateRenderingContextCommon(
+      bool aWantReferenceContext);
+
+  void SetDPI();
+  void ComputeClientRectUsingScreen(nsRect* outRect);
+  void ComputeFullAreaUsingScreen(nsRect* outRect);
+  already_AddRefed<mozilla::widget::Screen> FindScreen();
+
+  // Return false if the surface is not right
+  bool CalcPrintingSize();
+  void UpdateAppUnitsForFullZoom();
+
+  nscoord mWidth;
+  nscoord mHeight;
+  int32_t mAppUnitsPerDevPixel;
+  int32_t mAppUnitsPerDevPixelAtUnitFullZoom;
+  int32_t mAppUnitsPerPhysicalInch;
+  float mFullZoom;
+  float mPrintingScale;
+  gfxPoint mPrintingTranslate;
+
+  nsCOMPtr<nsIWidget> mWidget;
+  nsCOMPtr<nsIDeviceContextSpec> mDeviceContextSpec;
+  RefPtr<PrintTarget> mPrintTarget;
+  bool mIsCurrentlyPrintingDoc;
+  bool mIsInitialized = false;
+};
+
+#endif /* _NS_DEVICECONTEXT_H_ */
diff --git a/gfx/src/nsFont.cpp b/gfx/src/nsFont.cpp
new file mode 100644
index 0000000000..19f15b1db1
--- /dev/null
+++ b/gfx/src/nsFont.cpp
@@ -0,0 +1,290 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsFont.h"
+#include "gfxFont.h"          // for gfxFontStyle
+#include "gfxFontFeatures.h"  // for gfxFontFeature, etc
+#include "gfxFontUtils.h"     // for TRUETYPE_TAG
+#include "mozilla/ServoStyleConstsInlines.h"
+#include "nsCRT.h"    // for nsCRT
+#include "nsDebug.h"  // for NS_ASSERTION
+#include "nsISupports.h"
+#include "nsUnicharUtils.h"
+#include "nscore.h"  // for char16_t
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/gfx/2D.h"
+
+using namespace mozilla;
+
+nsFont::nsFont(const StyleFontFamily& aFamily, mozilla::Length aSize)
+    : family(aFamily), size(aSize) {}
+
+nsFont::nsFont(StyleGenericFontFamily aGenericType, mozilla::Length aSize)
+    : family(*Servo_FontFamily_Generic(aGenericType)), size(aSize) {}
+
+nsFont::nsFont(const nsFont& aOther) = default;
+
+nsFont::~nsFont() = default;
+
+nsFont& nsFont::operator=(const nsFont&) = default;
+
+bool nsFont::Equals(const nsFont& aOther) const {
+  return CalcDifference(aOther) == MaxDifference::eNone;
+}
+
+nsFont::MaxDifference nsFont::CalcDifference(const nsFont& aOther) const {
+  if ((style != aOther.style) || (weight != aOther.weight) ||
+      (stretch != aOther.stretch) || (size != aOther.size) ||
+      (sizeAdjust != aOther.sizeAdjust) || (family != aOther.family) ||
+      (kerning != aOther.kerning) || (opticalSizing != aOther.opticalSizing) ||
+      (synthesisWeight != aOther.synthesisWeight) ||
+      (synthesisStyle != aOther.synthesisStyle) ||
+      (synthesisSmallCaps != aOther.synthesisSmallCaps) ||
+      (fontFeatureSettings != aOther.fontFeatureSettings) ||
+      (fontVariationSettings != aOther.fontVariationSettings) ||
+      (languageOverride != aOther.languageOverride) ||
+      (variantAlternates != aOther.variantAlternates) ||
+      (variantCaps != aOther.variantCaps) ||
+      (variantEastAsian != aOther.variantEastAsian) ||
+      (variantLigatures != aOther.variantLigatures) ||
+      (variantNumeric != aOther.variantNumeric) ||
+      (variantPosition != aOther.variantPosition) ||
+      (variantWidth != aOther.variantWidth) ||
+      (variantEmoji != aOther.variantEmoji)) {
+    return MaxDifference::eLayoutAffecting;
+  }
+
+  if ((smoothing != aOther.smoothing) ||
+      (fontSmoothingBackgroundColor != aOther.fontSmoothingBackgroundColor)) {
+    return MaxDifference::eVisual;
+  }
+
+  return MaxDifference::eNone;
+}
+
+// mapping from bitflag to font feature tag/value pair
+//
+// these need to be kept in sync with the constants listed
+// in gfxFontConstants.h (e.g. NS_FONT_VARIANT_EAST_ASIAN_JIS78)
+
+// NS_FONT_VARIANT_EAST_ASIAN_xxx values
+const gfxFontFeature eastAsianDefaults[] = {
+    {TRUETYPE_TAG('j', 'p', '7', '8'), 1},
+    {TRUETYPE_TAG('j', 'p', '8', '3'), 1},
+    {TRUETYPE_TAG('j', 'p', '9', '0'), 1},
+    {TRUETYPE_TAG('j', 'p', '0', '4'), 1},
+    {TRUETYPE_TAG('s', 'm', 'p', 'l'), 1},
+    {TRUETYPE_TAG('t', 'r', 'a', 'd'), 1},
+    {TRUETYPE_TAG('f', 'w', 'i', 'd'), 1},
+    {TRUETYPE_TAG('p', 'w', 'i', 'd'), 1},
+    {TRUETYPE_TAG('r', 'u', 'b', 'y'), 1}};
+
+static_assert(MOZ_ARRAY_LENGTH(eastAsianDefaults) ==
+                  NS_FONT_VARIANT_EAST_ASIAN_COUNT,
+              "eastAsianDefaults[] should be correct");
+
+// NS_FONT_VARIANT_LIGATURES_xxx values
+const gfxFontFeature ligDefaults[] = {
+    {TRUETYPE_TAG('l', 'i', 'g', 'a'), 0},  // none value means all off
+    {TRUETYPE_TAG('l', 'i', 'g', 'a'), 1},
+    {TRUETYPE_TAG('l', 'i', 'g', 'a'), 0},
+    {TRUETYPE_TAG('d', 'l', 'i', 'g'), 1},
+    {TRUETYPE_TAG('d', 'l', 'i', 'g'), 0},
+    {TRUETYPE_TAG('h', 'l', 'i', 'g'), 1},
+    {TRUETYPE_TAG('h', 'l', 'i', 'g'), 0},
+    {TRUETYPE_TAG('c', 'a', 'l', 't'), 1},
+    {TRUETYPE_TAG('c', 'a', 'l', 't'), 0}};
+
+static_assert(MOZ_ARRAY_LENGTH(ligDefaults) == NS_FONT_VARIANT_LIGATURES_COUNT,
+              "ligDefaults[] should be correct");
+
+// NS_FONT_VARIANT_NUMERIC_xxx values
+const gfxFontFeature numericDefaults[] = {
+    {TRUETYPE_TAG('l', 'n', 'u', 'm'), 1},
+    {TRUETYPE_TAG('o', 'n', 'u', 'm'), 1},
+    {TRUETYPE_TAG('p', 'n', 'u', 'm'), 1},
+    {TRUETYPE_TAG('t', 'n', 'u', 'm'), 1},
+    {TRUETYPE_TAG('f', 'r', 'a', 'c'), 1},
+    {TRUETYPE_TAG('a', 'f', 'r', 'c'), 1},
+    {TRUETYPE_TAG('z', 'e', 'r', 'o'), 1},
+    {TRUETYPE_TAG('o', 'r', 'd', 'n'), 1}};
+
+static_assert(MOZ_ARRAY_LENGTH(numericDefaults) ==
+                  NS_FONT_VARIANT_NUMERIC_COUNT,
+              "numericDefaults[] should be correct");
+
+static void AddFontFeaturesBitmask(uint32_t aValue, uint32_t aMin,
+                                   uint32_t aMax,
+                                   const gfxFontFeature aFeatureDefaults[],
+                                   nsTArray<gfxFontFeature>& aFeaturesOut)
+
+{
+  uint32_t i, m;
+
+  for (i = 0, m = aMin; m <= aMax; i++, m <<= 1) {
+    if (m & aValue) {
+      const gfxFontFeature& feature = aFeatureDefaults[i];
+      aFeaturesOut.AppendElement(feature);
+    }
+  }
+}
+
+static uint32_t FontFeatureTagForVariantWidth(uint32_t aVariantWidth) {
+  switch (aVariantWidth) {
+    case NS_FONT_VARIANT_WIDTH_FULL:
+      return TRUETYPE_TAG('f', 'w', 'i', 'd');
+    case NS_FONT_VARIANT_WIDTH_HALF:
+      return TRUETYPE_TAG('h', 'w', 'i', 'd');
+    case NS_FONT_VARIANT_WIDTH_THIRD:
+      return TRUETYPE_TAG('t', 'w', 'i', 'd');
+    case NS_FONT_VARIANT_WIDTH_QUARTER:
+      return TRUETYPE_TAG('q', 'w', 'i', 'd');
+    default:
+      return 0;
+  }
+}
+
+void nsFont::AddFontFeaturesToStyle(gfxFontStyle* aStyle,
+                                    bool aVertical) const {
+  // add in font-variant features
+  gfxFontFeature setting;
+
+  // -- kerning
+  setting.mTag = aVertical ? TRUETYPE_TAG('v', 'k', 'r', 'n')
+                           : TRUETYPE_TAG('k', 'e', 'r', 'n');
+  switch (kerning) {
+    case NS_FONT_KERNING_NONE:
+      setting.mValue = 0;
+      aStyle->featureSettings.AppendElement(setting);
+      break;
+    case NS_FONT_KERNING_NORMAL:
+      setting.mValue = 1;
+      aStyle->featureSettings.AppendElement(setting);
+      break;
+    default:
+      // auto case implies use user agent default
+      break;
+  }
+
+  // -- alternates
+  //
+  // NOTE(emilio): We handle historical-forms here because it doesn't depend on
+  // other values set by @font-face and thus may be less expensive to do here
+  // than after font-matching.
+  for (auto& alternate : variantAlternates.AsSpan()) {
+    if (alternate.IsHistoricalForms()) {
+      setting.mValue = 1;
+      setting.mTag = TRUETYPE_TAG('h', 'i', 's', 't');
+      aStyle->featureSettings.AppendElement(setting);
+      break;
+    }
+  }
+
+  // -- copy font-specific alternate info into style
+  //    (this will be resolved after font-matching occurs)
+  aStyle->variantAlternates = variantAlternates;
+
+  // -- caps
+  aStyle->variantCaps = variantCaps;
+
+  // -- east-asian
+  if (variantEastAsian) {
+    AddFontFeaturesBitmask(variantEastAsian, NS_FONT_VARIANT_EAST_ASIAN_JIS78,
+                           NS_FONT_VARIANT_EAST_ASIAN_RUBY, eastAsianDefaults,
+                           aStyle->featureSettings);
+  }
+
+  // -- ligatures
+  if (variantLigatures) {
+    AddFontFeaturesBitmask(variantLigatures, NS_FONT_VARIANT_LIGATURES_NONE,
+                           NS_FONT_VARIANT_LIGATURES_NO_CONTEXTUAL, ligDefaults,
+                           aStyle->featureSettings);
+
+    if (variantLigatures & NS_FONT_VARIANT_LIGATURES_COMMON) {
+      // liga already enabled, need to enable clig also
+      setting.mTag = TRUETYPE_TAG('c', 'l', 'i', 'g');
+      setting.mValue = 1;
+      aStyle->featureSettings.AppendElement(setting);
+    } else if (variantLigatures & NS_FONT_VARIANT_LIGATURES_NO_COMMON) {
+      // liga already disabled, need to disable clig also
+      setting.mTag = TRUETYPE_TAG('c', 'l', 'i', 'g');
+      setting.mValue = 0;
+      aStyle->featureSettings.AppendElement(setting);
+    } else if (variantLigatures & NS_FONT_VARIANT_LIGATURES_NONE) {
+      // liga already disabled, need to disable dlig, hlig, calt, clig
+      setting.mValue = 0;
+      setting.mTag = TRUETYPE_TAG('d', 'l', 'i', 'g');
+      aStyle->featureSettings.AppendElement(setting);
+      setting.mTag = TRUETYPE_TAG('h', 'l', 'i', 'g');
+      aStyle->featureSettings.AppendElement(setting);
+      setting.mTag = TRUETYPE_TAG('c', 'a', 'l', 't');
+      aStyle->featureSettings.AppendElement(setting);
+      setting.mTag = TRUETYPE_TAG('c', 'l', 'i', 'g');
+      aStyle->featureSettings.AppendElement(setting);
+    }
+  }
+
+  // -- numeric
+  if (variantNumeric) {
+    AddFontFeaturesBitmask(variantNumeric, NS_FONT_VARIANT_NUMERIC_LINING,
+                           NS_FONT_VARIANT_NUMERIC_ORDINAL, numericDefaults,
+                           aStyle->featureSettings);
+  }
+
+  // -- position
+  aStyle->variantSubSuper = variantPosition;
+
+  // -- width
+  setting.mTag = FontFeatureTagForVariantWidth(variantWidth);
+  if (setting.mTag) {
+    setting.mValue = 1;
+    aStyle->featureSettings.AppendElement(setting);
+  }
+
+  // indicate common-path case when neither variantCaps or variantSubSuper are
+  // set
+  aStyle->noFallbackVariantFeatures =
+      (aStyle->variantCaps == NS_FONT_VARIANT_CAPS_NORMAL) &&
+      (variantPosition == NS_FONT_VARIANT_POSITION_NORMAL);
+
+  // If the feature list is not empty, we insert a "fake" feature with tag=0
+  // as delimiter between the above "high-level" features from font-variant-*
+  // etc and those coming from the low-level font-feature-settings property.
+  // This will allow us to distinguish high- and low-level settings when it
+  // comes to potentially disabling ligatures because of letter-spacing.
+  if (!aStyle->featureSettings.IsEmpty() || !fontFeatureSettings.IsEmpty()) {
+    aStyle->featureSettings.AppendElement(gfxFontFeature{0, 0});
+  }
+
+  // add in features from font-feature-settings
+  aStyle->featureSettings.AppendElements(fontFeatureSettings);
+
+  // enable grayscale antialiasing for text
+  if (smoothing == NS_FONT_SMOOTHING_GRAYSCALE) {
+    aStyle->useGrayscaleAntialiasing = true;
+  }
+
+  aStyle->fontSmoothingBackgroundColor = fontSmoothingBackgroundColor.ToColor();
+}
+
+void nsFont::AddFontVariationsToStyle(gfxFontStyle* aStyle) const {
+  // If auto optical sizing is enabled, and if there's no 'opsz' axis in
+  // fontVariationSettings, then set the automatic value on the style.
+  class VariationTagComparator {
+   public:
+    bool Equals(const gfxFontVariation& aVariation, uint32_t aTag) const {
+      return aVariation.mTag == aTag;
+    }
+  };
+  const uint32_t kTagOpsz = TRUETYPE_TAG('o', 'p', 's', 'z');
+  if (opticalSizing == NS_FONT_OPTICAL_SIZING_AUTO &&
+      !fontVariationSettings.Contains(kTagOpsz, VariationTagComparator())) {
+    aStyle->autoOpticalSize = size.ToCSSPixels();
+  }
+
+  // Add in arbitrary values from font-variation-settings
+  aStyle->variationSettings.AppendElements(fontVariationSettings);
+}
diff --git a/gfx/src/nsFont.h b/gfx/src/nsFont.h
new file mode 100644
index 0000000000..3e8bffa5c1
--- /dev/null
+++ b/gfx/src/nsFont.h
@@ -0,0 +1,128 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsFont_h___
+#define nsFont_h___
+
+#include <cstdint>
+#include "gfxFontConstants.h"  // for NS_FONT_KERNING_AUTO, etc
+#include "gfxFontVariations.h"
+#include "mozilla/ServoStyleConsts.h"
+#include "mozilla/StyleColorInlines.h"  // for StyleAbsoluteColor
+#include "nsTArray.h"                   // for nsTArray
+
+struct gfxFontFeature;
+struct gfxFontStyle;
+
+// Font structure.
+struct nsFont final {
+  typedef mozilla::FontStretch FontStretch;
+  typedef mozilla::FontSlantStyle FontSlantStyle;
+  typedef mozilla::FontWeight FontWeight;
+
+  // List of font families, either named or generic.
+  mozilla::StyleFontFamily family;
+
+  // Font features from CSS font-feature-settings
+  CopyableTArray<gfxFontFeature> fontFeatureSettings;
+
+  // Font variations from CSS font-variation-settings
+  CopyableTArray<gfxFontVariation> fontVariationSettings;
+
+  // The logical size of the font, in CSS Pixels
+  mozilla::NonNegativeLength size{0};
+
+  // The aspect-value (ie., the ratio actualsize:actualxheight) that any
+  // actual physical font created from this font structure must have when
+  // rendering or measuring a string. The value must be nonnegative.
+  mozilla::StyleFontSizeAdjust sizeAdjust =
+      mozilla::StyleFontSizeAdjust::None();
+
+  // The estimated background color behind the text. Enables a special
+  // rendering mode when the alpha component > 0. Only used for text in the
+  // chrome.
+  mozilla::StyleAbsoluteColor fontSmoothingBackgroundColor =
+      mozilla::StyleAbsoluteColor::Transparent();
+
+  // Language system tag, to override document language;
+  // this is an OpenType "language system" tag represented as a 32-bit integer
+  // (see http://www.microsoft.com/typography/otspec/languagetags.htm).
+  uint32_t languageOverride = 0;
+
+  // Font-selection/rendering properties corresponding to CSS font-style,
+  // font-weight, font-stretch. These are all 16-bit types.
+  FontSlantStyle style = FontSlantStyle::NORMAL;
+  FontWeight weight = FontWeight::NORMAL;
+  FontStretch stretch = FontStretch::NORMAL;
+
+  // Some font-variant-alternates property values require
+  // font-specific settings defined via @font-feature-values rules.
+  // These are resolved *after* font matching occurs.
+  mozilla::StyleFontVariantAlternates variantAlternates;
+
+  // Variant subproperties
+  uint16_t variantLigatures = NS_FONT_VARIANT_LIGATURES_NORMAL;
+  uint16_t variantEastAsian = NS_FONT_VARIANT_EAST_ASIAN_NORMAL;
+
+  uint8_t variantCaps = NS_FONT_VARIANT_CAPS_NORMAL;
+  uint8_t variantNumeric = NS_FONT_VARIANT_NUMERIC_NORMAL;
+  uint8_t variantPosition = NS_FONT_VARIANT_POSITION_NORMAL;
+  uint8_t variantWidth = NS_FONT_VARIANT_WIDTH_NORMAL;
+  StyleFontVariantEmoji variantEmoji = StyleFontVariantEmoji::Normal;
+
+  // Smoothing - controls subpixel-antialiasing (currently OSX only)
+  uint8_t smoothing = NS_FONT_SMOOTHING_AUTO;
+
+  // Kerning
+  uint8_t kerning = NS_FONT_KERNING_AUTO;
+
+  // Whether automatic optical sizing should be applied to variation fonts
+  // that include an 'opsz' axis
+  uint8_t opticalSizing = NS_FONT_OPTICAL_SIZING_AUTO;
+
+  // Synthesis setting, controls use of fake bolding/italics/small-caps
+  mozilla::StyleFontSynthesis synthesisWeight =
+      mozilla::StyleFontSynthesis::Auto;
+  mozilla::StyleFontSynthesis synthesisStyle =
+      mozilla::StyleFontSynthesis::Auto;
+  mozilla::StyleFontSynthesis synthesisSmallCaps =
+      mozilla::StyleFontSynthesis::Auto;
+
+  // initialize the font with a fontlist
+  nsFont(const mozilla::StyleFontFamily&, mozilla::Length aSize);
+
+  // initialize the font with a single generic
+  nsFont(mozilla::StyleGenericFontFamily, mozilla::Length aSize);
+
+  // Make a copy of the given font
+  nsFont(const nsFont& aFont);
+
+  // leave members uninitialized
+  nsFont() = default;
+  ~nsFont();
+
+  bool operator==(const nsFont& aOther) const { return Equals(aOther); }
+
+  bool operator!=(const nsFont& aOther) const { return !Equals(aOther); }
+
+  bool Equals(const nsFont& aOther) const;
+
+  nsFont& operator=(const nsFont& aOther);
+
+  enum class MaxDifference : uint8_t { eNone, eVisual, eLayoutAffecting };
+
+  MaxDifference CalcDifference(const nsFont& aOther) const;
+
+  // Add featureSettings into style
+  void AddFontFeaturesToStyle(gfxFontStyle* aStyle, bool aVertical) const;
+
+  void AddFontVariationsToStyle(gfxFontStyle* aStyle) const;
+};
+
+#define NS_FONT_VARIANT_NORMAL 0
+#define NS_FONT_VARIANT_SMALL_CAPS 1
+
+#endif /* nsFont_h___ */
diff --git a/gfx/src/nsFontCache.cpp b/gfx/src/nsFontCache.cpp
new file mode 100644
index 0000000000..8b40d25eff
--- /dev/null
+++ b/gfx/src/nsFontCache.cpp
@@ -0,0 +1,156 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsFontCache.h"
+
+#include "gfxTextRun.h"
+#include "mozilla/Services.h"
+#include "mozilla/ServoUtils.h"
+#include "nsCRT.h"
+
+using mozilla::services::GetObserverService;
+
+NS_IMPL_ISUPPORTS(nsFontCache, nsIObserver)
+
+// The Init and Destroy methods are necessary because it's not
+// safe to call AddObserver from a constructor or RemoveObserver
+// from a destructor.  That should be fixed.
+void nsFontCache::Init(nsPresContext* aContext) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  mContext = aContext;
+  // register as a memory-pressure observer to free font resources
+  // in low-memory situations.
+  nsCOMPtr<nsIObserverService> obs = GetObserverService();
+  if (obs) {
+    obs->AddObserver(this, "memory-pressure", false);
+  }
+
+  mLocaleLanguage = nsLanguageAtomService::GetService()->GetLocaleLanguage();
+  if (!mLocaleLanguage) {
+    mLocaleLanguage = NS_Atomize("x-western");
+  }
+}
+
+void nsFontCache::Destroy() {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  nsCOMPtr<nsIObserverService> obs = GetObserverService();
+  if (obs) {
+    obs->RemoveObserver(this, "memory-pressure");
+  }
+  Flush();
+}
+
+NS_IMETHODIMP
+nsFontCache::Observe(nsISupports*, const char* aTopic, const char16_t*) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  if (!nsCRT::strcmp(aTopic, "memory-pressure")) {
+    Compact();
+  }
+  return NS_OK;
+}
+
+already_AddRefed<nsFontMetrics> nsFontCache::GetMetricsFor(
+    const nsFont& aFont, const nsFontMetrics::Params& aParams) {
+  // We may eventually want to put an nsFontCache on canvas2d workers, but for
+  // now it is only used by the main-thread layout code and stylo.
+  mozilla::AssertIsMainThreadOrServoFontMetricsLocked();
+
+  nsAtom* language = aParams.language && !aParams.language->IsEmpty()
+                         ? aParams.language
+                         : mLocaleLanguage.get();
+
+  // First check our cache
+  // start from the end, which is where we put the most-recent-used element
+  const int32_t n = mFontMetrics.Length() - 1;
+  for (int32_t i = n; i >= 0; --i) {
+    nsFontMetrics* fm = mFontMetrics[i];
+    if (fm->Font().Equals(aFont) &&
+        fm->GetUserFontSet() == aParams.userFontSet &&
+        fm->Language() == language &&
+        fm->Orientation() == aParams.orientation &&
+        fm->ExplicitLanguage() == aParams.explicitLanguage) {
+      if (i != n) {
+        // promote it to the end of the cache
+        mFontMetrics.RemoveElementAt(i);
+        mFontMetrics.AppendElement(fm);
+      }
+      fm->GetThebesFontGroup()->UpdateUserFonts();
+      return do_AddRef(fm);
+    }
+  }
+
+  // It's not in the cache. Get font metrics and then cache them.
+  // If the cache has reached its size limit, drop the older half of the
+  // entries; but if we're on a stylo thread (the usual case), we have
+  // to post a task back to the main thread to do the flush.
+  if (n >= kMaxCacheEntries - 1 && !mFlushPending) {
+    if (NS_IsMainThread()) {
+      Flush(mFontMetrics.Length() - kMaxCacheEntries / 2);
+    } else {
+      mFlushPending = true;
+      nsCOMPtr<nsIRunnable> flushTask = new FlushFontMetricsTask(this);
+      MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThread(flushTask));
+    }
+  }
+
+  nsFontMetrics::Params params = aParams;
+  params.language = language;
+  RefPtr<nsFontMetrics> fm = new nsFontMetrics(aFont, params, mContext);
+  // the mFontMetrics list has the "head" at the end, because append
+  // is cheaper than insert
+  mFontMetrics.AppendElement(do_AddRef(fm).take());
+  return fm.forget();
+}
+
+void nsFontCache::UpdateUserFonts(gfxUserFontSet* aUserFontSet) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  for (nsFontMetrics* fm : mFontMetrics) {
+    gfxFontGroup* fg = fm->GetThebesFontGroup();
+    if (fg->GetUserFontSet() == aUserFontSet) {
+      fg->UpdateUserFonts();
+    }
+  }
+}
+
+void nsFontCache::FontMetricsDeleted(const nsFontMetrics* aFontMetrics) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  mFontMetrics.RemoveElement(aFontMetrics);
+}
+
+void nsFontCache::Compact() {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  // Need to loop backward because the running element can be removed on
+  // the way
+  for (int32_t i = mFontMetrics.Length() - 1; i >= 0; --i) {
+    nsFontMetrics* fm = mFontMetrics[i];
+    nsFontMetrics* oldfm = fm;
+    // Destroy() isn't here because we want our device context to be
+    // notified
+    NS_RELEASE(fm);  // this will reset fm to nullptr
+    // if the font is really gone, it would have called back in
+    // FontMetricsDeleted() and would have removed itself
+    if (mFontMetrics.IndexOf(oldfm) != mFontMetrics.NoIndex) {
+      // nope, the font is still there, so let's hold onto it too
+      NS_ADDREF(oldfm);
+    }
+  }
+}
+
+// Flush the aFlushCount oldest entries, or all if (aFlushCount < 0)
+void nsFontCache::Flush(int32_t aFlushCount) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  int32_t n = aFlushCount < 0
+                  ? mFontMetrics.Length()
+                  : std::min<int32_t>(aFlushCount, mFontMetrics.Length());
+  for (int32_t i = n - 1; i >= 0; --i) {
+    nsFontMetrics* fm = mFontMetrics[i];
+    // Destroy() will unhook our device context from the fm so that we
+    // won't waste time in triggering the notification of
+    // FontMetricsDeleted() in the subsequent release
+    fm->Destroy();
+    NS_RELEASE(fm);
+  }
+  mFontMetrics.RemoveElementsAt(0, n);
+}
diff --git a/gfx/src/nsFontCache.h b/gfx/src/nsFontCache.h
new file mode 100644
index 0000000000..2d84e1f12f
--- /dev/null
+++ b/gfx/src/nsFontCache.h
@@ -0,0 +1,85 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _NS_FONTCACHE_H_
+#define _NS_FONTCACHE_H_
+
+#include <stdint.h>
+#include <sys/types.h>
+#include "mozilla/RefPtr.h"
+#include "nsCOMPtr.h"
+#include "nsFontMetrics.h"
+#include "nsIObserver.h"
+#include "nsISupports.h"
+#include "nsTArray.h"
+#include "nsThreadUtils.h"
+
+class gfxUserFontSet;
+class nsAtom;
+class nsPresContext;
+struct nsFont;
+
+class nsFontCache final : public nsIObserver {
+ public:
+  nsFontCache() : mContext(nullptr) {}
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  void Init(nsPresContext* aContext);
+  void Destroy();
+
+  already_AddRefed<nsFontMetrics> GetMetricsFor(
+      const nsFont& aFont, const nsFontMetrics::Params& aParams);
+
+  void FontMetricsDeleted(const nsFontMetrics* aFontMetrics);
+  void Compact();
+
+  // Flush aFlushCount oldest entries, or all if aFlushCount is negative
+  void Flush(int32_t aFlushCount = -1);
+
+  void UpdateUserFonts(gfxUserFontSet* aUserFontSet);
+
+ protected:
+  // If the array of cached entries is about to exceed this threshold,
+  // we'll discard the oldest ones so as to keep the size reasonable.
+  // In practice, the great majority of cache hits are among the last
+  // few entries; keeping thousands of older entries becomes counter-
+  // productive because it can then take too long to scan the cache.
+  static const int32_t kMaxCacheEntries = 128;
+
+  ~nsFontCache() = default;
+
+  nsPresContext* mContext;  // owner
+  RefPtr<nsAtom> mLocaleLanguage;
+
+  // We may not flush older entries immediately the array reaches
+  // kMaxCacheEntries length, because this usually happens on a stylo
+  // thread where we can't safely delete metrics objects. So we allocate an
+  // oversized autoarray buffer here, so that we're unlikely to overflow
+  // it and need separate heap allocation before the flush happens on the
+  // main thread.
+  AutoTArray<nsFontMetrics*, kMaxCacheEntries * 2> mFontMetrics;
+
+  bool mFlushPending = false;
+
+  class FlushFontMetricsTask : public mozilla::Runnable {
+   public:
+    explicit FlushFontMetricsTask(nsFontCache* aCache)
+        : mozilla::Runnable("FlushFontMetricsTask"), mCache(aCache) {}
+    NS_IMETHOD Run() override {
+      // Partially flush the cache, leaving the kMaxCacheEntries/2 most
+      // recent entries.
+      mCache->Flush(mCache->mFontMetrics.Length() - kMaxCacheEntries / 2);
+      mCache->mFlushPending = false;
+      return NS_OK;
+    }
+
+   private:
+    RefPtr<nsFontCache> mCache;
+  };
+};
+
+#endif /* _NS_FONTCACHE_H_ */
diff --git a/gfx/src/nsFontMetrics.cpp b/gfx/src/nsFontMetrics.cpp
new file mode 100644
index 0000000000..a3e4d5e312
--- /dev/null
+++ b/gfx/src/nsFontMetrics.cpp
@@ -0,0 +1,402 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsFontMetrics.h"
+#include <math.h>                // for floor, ceil
+#include <algorithm>             // for max
+#include "gfxContext.h"          // for gfxContext
+#include "gfxFontConstants.h"    // for NS_FONT_SYNTHESIS_*
+#include "gfxPlatform.h"         // for gfxPlatform
+#include "gfxPoint.h"            // for gfxPoint
+#include "gfxRect.h"             // for gfxRect
+#include "gfxTextRun.h"          // for gfxFontGroup
+#include "gfxTypes.h"            // for gfxFloat
+#include "nsAtom.h"              // for nsAtom
+#include "nsBoundingMetrics.h"   // for nsBoundingMetrics
+#include "nsDebug.h"             // for NS_ERROR
+#include "nsDeviceContext.h"     // for nsDeviceContext
+#include "nsMathUtils.h"         // for NS_round
+#include "nsPresContext.h"       // for nsPresContext
+#include "nsString.h"            // for nsString
+#include "nsStyleConsts.h"       // for StyleHyphens::None
+#include "mozilla/Assertions.h"  // for MOZ_ASSERT
+#include "mozilla/UniquePtr.h"   // for UniquePtr
+
+class gfxUserFontSet;
+using namespace mozilla;
+
+namespace {
+
+class AutoTextRun {
+ public:
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+
+  AutoTextRun(const nsFontMetrics* aMetrics, DrawTarget* aDrawTarget,
+              const char* aString, uint32_t aLength) {
+    mTextRun = aMetrics->GetThebesFontGroup()->MakeTextRun(
+        reinterpret_cast<const uint8_t*>(aString), aLength, aDrawTarget,
+        aMetrics->AppUnitsPerDevPixel(), ComputeFlags(aMetrics),
+        nsTextFrameUtils::Flags(), nullptr);
+  }
+
+  AutoTextRun(const nsFontMetrics* aMetrics, DrawTarget* aDrawTarget,
+              const char16_t* aString, uint32_t aLength) {
+    mTextRun = aMetrics->GetThebesFontGroup()->MakeTextRun(
+        aString, aLength, aDrawTarget, aMetrics->AppUnitsPerDevPixel(),
+        ComputeFlags(aMetrics), nsTextFrameUtils::Flags(), nullptr);
+  }
+
+  gfxTextRun* get() const { return mTextRun.get(); }
+  gfxTextRun* operator->() const { return mTextRun.get(); }
+
+ private:
+  static gfx::ShapedTextFlags ComputeFlags(const nsFontMetrics* aMetrics) {
+    gfx::ShapedTextFlags flags = gfx::ShapedTextFlags();
+    if (aMetrics->GetTextRunRTL()) {
+      flags |= gfx::ShapedTextFlags::TEXT_IS_RTL;
+    }
+    if (aMetrics->GetVertical()) {
+      switch (aMetrics->GetTextOrientation()) {
+        case StyleTextOrientation::Mixed:
+          flags |= gfx::ShapedTextFlags::TEXT_ORIENT_VERTICAL_MIXED;
+          break;
+        case StyleTextOrientation::Upright:
+          flags |= gfx::ShapedTextFlags::TEXT_ORIENT_VERTICAL_UPRIGHT;
+          break;
+        case StyleTextOrientation::Sideways:
+          flags |= gfx::ShapedTextFlags::TEXT_ORIENT_VERTICAL_SIDEWAYS_RIGHT;
+          break;
+      }
+    }
+    return flags;
+  }
+
+  RefPtr<gfxTextRun> mTextRun;
+};
+
+class StubPropertyProvider final : public gfxTextRun::PropertyProvider {
+ public:
+  void GetHyphenationBreaks(
+      gfxTextRun::Range aRange,
+      gfxTextRun::HyphenType* aBreakBefore) const override {
+    NS_ERROR(
+        "This shouldn't be called because we never call BreakAndMeasureText");
+  }
+  mozilla::StyleHyphens GetHyphensOption() const override {
+    NS_ERROR(
+        "This shouldn't be called because we never call BreakAndMeasureText");
+    return mozilla::StyleHyphens::None;
+  }
+  gfxFloat GetHyphenWidth() const override {
+    NS_ERROR("This shouldn't be called because we never enable hyphens");
+    return 0;
+  }
+  already_AddRefed<mozilla::gfx::DrawTarget> GetDrawTarget() const override {
+    NS_ERROR("This shouldn't be called because we never enable hyphens");
+    return nullptr;
+  }
+  uint32_t GetAppUnitsPerDevUnit() const override {
+    NS_ERROR("This shouldn't be called because we never enable hyphens");
+    return 60;
+  }
+  void GetSpacing(gfxTextRun::Range aRange, Spacing* aSpacing) const override {
+    NS_ERROR("This shouldn't be called because we never enable spacing");
+  }
+  gfx::ShapedTextFlags GetShapedTextFlags() const override {
+    NS_ERROR("This shouldn't be called because we never enable hyphens");
+    return gfx::ShapedTextFlags();
+  }
+};
+
+}  // namespace
+
+nsFontMetrics::nsFontMetrics(const nsFont& aFont, const Params& aParams,
+                             nsPresContext* aContext)
+    : mFont(aFont),
+      mLanguage(aParams.language),
+      mPresContext(aContext),
+      mP2A(aContext->DeviceContext()->AppUnitsPerDevPixel()),
+      mOrientation(aParams.orientation),
+      mExplicitLanguage(aParams.explicitLanguage),
+      mTextRunRTL(false),
+      mVertical(false),
+      mTextOrientation(mozilla::StyleTextOrientation::Mixed) {
+  gfxFontStyle style(aFont.style, aFont.weight, aFont.stretch,
+                     gfxFloat(aFont.size.ToAppUnits()) / mP2A, aFont.sizeAdjust,
+                     aFont.family.is_system_font,
+                     aContext->DeviceContext()->IsPrinterContext(),
+                     aFont.synthesisWeight == StyleFontSynthesis::Auto,
+                     aFont.synthesisStyle == StyleFontSynthesis::Auto,
+                     aFont.synthesisSmallCaps == StyleFontSynthesis::Auto,
+                     aFont.languageOverride);
+
+  aFont.AddFontFeaturesToStyle(&style, mOrientation == eVertical);
+  style.featureValueLookup = aParams.featureValueLookup;
+
+  aFont.AddFontVariationsToStyle(&style);
+
+  gfxFloat devToCssSize = gfxFloat(mP2A) / gfxFloat(AppUnitsPerCSSPixel());
+  mFontGroup = new gfxFontGroup(
+      mPresContext, aFont.family.families, &style, mLanguage, mExplicitLanguage,
+      aParams.textPerf, aParams.userFontSet, devToCssSize, aFont.variantEmoji);
+}
+
+nsFontMetrics::~nsFontMetrics() {
+  // Should not be dropped by stylo
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mPresContext) {
+    mPresContext->FontMetricsDeleted(this);
+  }
+}
+
+void nsFontMetrics::Destroy() { mPresContext = nullptr; }
+
+// XXXTODO get rid of this macro
+#define ROUND_TO_TWIPS(x) (nscoord) floor(((x)*mP2A) + 0.5)
+#define CEIL_TO_TWIPS(x) (nscoord) ceil((x)*mP2A)
+
+static const gfxFont::Metrics& GetMetrics(
+    const nsFontMetrics* aFontMetrics,
+    nsFontMetrics::FontOrientation aOrientation) {
+  RefPtr<gfxFont> font =
+      aFontMetrics->GetThebesFontGroup()->GetFirstValidFont();
+  return font->GetMetrics(aOrientation);
+}
+
+static const gfxFont::Metrics& GetMetrics(const nsFontMetrics* aFontMetrics) {
+  return GetMetrics(aFontMetrics, aFontMetrics->Orientation());
+}
+
+nscoord nsFontMetrics::XHeight() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).xHeight);
+}
+
+nscoord nsFontMetrics::CapHeight() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).capHeight);
+}
+
+nscoord nsFontMetrics::SuperscriptOffset() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).emHeight *
+                        NS_FONT_SUPERSCRIPT_OFFSET_RATIO);
+}
+
+nscoord nsFontMetrics::SubscriptOffset() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).emHeight *
+                        NS_FONT_SUBSCRIPT_OFFSET_RATIO);
+}
+
+void nsFontMetrics::GetStrikeout(nscoord& aOffset, nscoord& aSize) const {
+  aOffset = ROUND_TO_TWIPS(GetMetrics(this).strikeoutOffset);
+  aSize = ROUND_TO_TWIPS(GetMetrics(this).strikeoutSize);
+}
+
+void nsFontMetrics::GetUnderline(nscoord& aOffset, nscoord& aSize) const {
+  aOffset = ROUND_TO_TWIPS(mFontGroup->GetUnderlineOffset());
+  aSize = ROUND_TO_TWIPS(GetMetrics(this).underlineSize);
+}
+
+// GetMaxAscent/GetMaxDescent/GetMaxHeight must contain the
+// text-decoration lines drawable area. See bug 421353.
+// BE CAREFUL for rounding each values. The logic MUST be same as
+// nsCSSRendering::GetTextDecorationRectInternal's.
+
+static gfxFloat ComputeMaxDescent(const gfxFont::Metrics& aMetrics,
+                                  gfxFontGroup* aFontGroup) {
+  gfxFloat offset = floor(-aFontGroup->GetUnderlineOffset() + 0.5);
+  gfxFloat size = NS_round(aMetrics.underlineSize);
+  gfxFloat minDescent = offset + size;
+  return floor(std::max(minDescent, aMetrics.maxDescent) + 0.5);
+}
+
+static gfxFloat ComputeMaxAscent(const gfxFont::Metrics& aMetrics) {
+  return floor(aMetrics.maxAscent + 0.5);
+}
+
+nscoord nsFontMetrics::InternalLeading() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).internalLeading);
+}
+
+nscoord nsFontMetrics::ExternalLeading() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).externalLeading);
+}
+
+nscoord nsFontMetrics::EmHeight() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).emHeight);
+}
+
+nscoord nsFontMetrics::EmAscent() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).emAscent);
+}
+
+nscoord nsFontMetrics::EmDescent() const {
+  return ROUND_TO_TWIPS(GetMetrics(this).emDescent);
+}
+
+nscoord nsFontMetrics::MaxHeight() const {
+  return CEIL_TO_TWIPS(ComputeMaxAscent(GetMetrics(this))) +
+         CEIL_TO_TWIPS(ComputeMaxDescent(GetMetrics(this), mFontGroup));
+}
+
+nscoord nsFontMetrics::MaxAscent() const {
+  return CEIL_TO_TWIPS(ComputeMaxAscent(GetMetrics(this)));
+}
+
+nscoord nsFontMetrics::MaxDescent() const {
+  return CEIL_TO_TWIPS(ComputeMaxDescent(GetMetrics(this), mFontGroup));
+}
+
+nscoord nsFontMetrics::MaxAdvance() const {
+  return CEIL_TO_TWIPS(GetMetrics(this).maxAdvance);
+}
+
+nscoord nsFontMetrics::AveCharWidth() const {
+  // Use CEIL instead of ROUND for consistency with GetMaxAdvance
+  return CEIL_TO_TWIPS(GetMetrics(this).aveCharWidth);
+}
+
+nscoord nsFontMetrics::ZeroOrAveCharWidth() const {
+  return CEIL_TO_TWIPS(GetMetrics(this).ZeroOrAveCharWidth());
+}
+
+nscoord nsFontMetrics::SpaceWidth() const {
+  // For vertical text with mixed or sideways orientation, we want the
+  // width of a horizontal space (even if we're using vertical line-spacing
+  // metrics, as with "writing-mode:vertical-*;text-orientation:mixed").
+  return CEIL_TO_TWIPS(
+      GetMetrics(this,
+                 mVertical && mTextOrientation == StyleTextOrientation::Upright
+                     ? eVertical
+                     : eHorizontal)
+          .spaceWidth);
+}
+
+int32_t nsFontMetrics::GetMaxStringLength() const {
+  const double x = 32767.0 / std::max(1.0, GetMetrics(this).maxAdvance);
+  int32_t len = (int32_t)floor(x);
+  return std::max(1, len);
+}
+
+nscoord nsFontMetrics::GetWidth(const char* aString, uint32_t aLength,
+                                DrawTarget* aDrawTarget) const {
+  if (aLength == 0) {
+    return 0;
+  }
+  if (aLength == 1 && aString[0] == ' ') {
+    return SpaceWidth();
+  }
+  StubPropertyProvider provider;
+  AutoTextRun textRun(this, aDrawTarget, aString, aLength);
+  if (textRun.get()) {
+    return NSToCoordRound(
+        textRun->GetAdvanceWidth(gfxTextRun::Range(0, aLength), &provider));
+  }
+  return 0;
+}
+
+nscoord nsFontMetrics::GetWidth(const char16_t* aString, uint32_t aLength,
+                                DrawTarget* aDrawTarget) const {
+  if (aLength == 0) {
+    return 0;
+  }
+  if (aLength == 1 && aString[0] == ' ') {
+    return SpaceWidth();
+  }
+  StubPropertyProvider provider;
+  AutoTextRun textRun(this, aDrawTarget, aString, aLength);
+  if (textRun.get()) {
+    return NSToCoordRound(
+        textRun->GetAdvanceWidth(gfxTextRun::Range(0, aLength), &provider));
+  }
+  return 0;
+}
+
+// Draw a string using this font handle on the surface passed in.
+void nsFontMetrics::DrawString(const char* aString, uint32_t aLength,
+                               nscoord aX, nscoord aY,
+                               gfxContext* aContext) const {
+  if (aLength == 0) {
+    return;
+  }
+  StubPropertyProvider provider;
+  AutoTextRun textRun(this, aContext->GetDrawTarget(), aString, aLength);
+  if (!textRun.get()) {
+    return;
+  }
+  gfx::Point pt(aX, aY);
+  gfxTextRun::Range range(0, aLength);
+  if (mTextRunRTL) {
+    if (mVertical) {
+      pt.y += textRun->GetAdvanceWidth(range, &provider);
+    } else {
+      pt.x += textRun->GetAdvanceWidth(range, &provider);
+    }
+  }
+  gfxTextRun::DrawParams params(aContext);
+  params.provider = &provider;
+  textRun->Draw(range, pt, params);
+}
+
+void nsFontMetrics::DrawString(
+    const char16_t* aString, uint32_t aLength, nscoord aX, nscoord aY,
+    gfxContext* aContext, DrawTarget* aTextRunConstructionDrawTarget) const {
+  if (aLength == 0) {
+    return;
+  }
+  StubPropertyProvider provider;
+  AutoTextRun textRun(this, aTextRunConstructionDrawTarget, aString, aLength);
+  if (!textRun.get()) {
+    return;
+  }
+  gfx::Point pt(aX, aY);
+  gfxTextRun::Range range(0, aLength);
+  if (mTextRunRTL) {
+    if (mVertical) {
+      pt.y += textRun->GetAdvanceWidth(range, &provider);
+    } else {
+      pt.x += textRun->GetAdvanceWidth(range, &provider);
+    }
+  }
+  gfxTextRun::DrawParams params(aContext);
+  params.provider = &provider;
+  textRun->Draw(range, pt, params);
+}
+
+static nsBoundingMetrics GetTextBoundingMetrics(
+    const nsFontMetrics* aMetrics, const char16_t* aString, uint32_t aLength,
+    mozilla::gfx::DrawTarget* aDrawTarget, gfxFont::BoundingBoxType aType) {
+  if (aLength == 0) {
+    return nsBoundingMetrics();
+  }
+  StubPropertyProvider provider;
+  AutoTextRun textRun(aMetrics, aDrawTarget, aString, aLength);
+  nsBoundingMetrics m;
+  if (textRun.get()) {
+    gfxTextRun::Metrics theMetrics = textRun->MeasureText(
+        gfxTextRun::Range(0, aLength), aType, aDrawTarget, &provider);
+
+    m.leftBearing = NSToCoordFloor(theMetrics.mBoundingBox.X());
+    m.rightBearing = NSToCoordCeil(theMetrics.mBoundingBox.XMost());
+    m.ascent = NSToCoordCeil(-theMetrics.mBoundingBox.Y());
+    m.descent = NSToCoordCeil(theMetrics.mBoundingBox.YMost());
+    m.width = NSToCoordRound(theMetrics.mAdvanceWidth);
+  }
+  return m;
+}
+
+nsBoundingMetrics nsFontMetrics::GetBoundingMetrics(
+    const char16_t* aString, uint32_t aLength, DrawTarget* aDrawTarget) const {
+  return GetTextBoundingMetrics(this, aString, aLength, aDrawTarget,
+                                gfxFont::TIGHT_HINTED_OUTLINE_EXTENTS);
+}
+
+nsBoundingMetrics nsFontMetrics::GetInkBoundsForInkOverflow(
+    const char16_t* aString, uint32_t aLength, DrawTarget* aDrawTarget) const {
+  return GetTextBoundingMetrics(this, aString, aLength, aDrawTarget,
+                                gfxFont::LOOSE_INK_EXTENTS);
+}
+
+gfxUserFontSet* nsFontMetrics::GetUserFontSet() const {
+  return mFontGroup->GetUserFontSet();
+}
diff --git a/gfx/src/nsFontMetrics.h b/gfx/src/nsFontMetrics.h
new file mode 100644
index 0000000000..55a45f6be1
--- /dev/null
+++ b/gfx/src/nsFontMetrics.h
@@ -0,0 +1,279 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSFONTMETRICS__H__
+#define NSFONTMETRICS__H__
+
+#include <stdint.h>              // for uint32_t
+#include <sys/types.h>           // for int32_t
+#include "mozilla/Assertions.h"  // for MOZ_ASSERT_HELPER2
+#include "mozilla/RefPtr.h"      // for RefPtr
+#include "nsCOMPtr.h"            // for nsCOMPtr
+#include "nsCoord.h"             // for nscoord
+#include "nsError.h"             // for nsresult
+#include "nsFont.h"              // for nsFont
+#include "nsISupports.h"         // for NS_INLINE_DECL_REFCOUNTING
+#include "nsStyleConsts.h"
+#include "nscore.h"  // for char16_t
+
+class gfxContext;
+class gfxFontGroup;
+class gfxUserFontSet;
+class gfxTextPerfMetrics;
+class nsPresContext;
+class nsAtom;
+struct nsBoundingMetrics;
+
+namespace mozilla {
+namespace gfx {
+class DrawTarget;
+}  // namespace gfx
+}  // namespace mozilla
+
+/**
+ * Font metrics
+ *
+ * This class may be somewhat misnamed. A better name might be
+ * nsFontList. The style system uses the nsFont struct for various
+ * font properties, one of which is font-family, which can contain a
+ * *list* of font names. The nsFont struct is "realized" by asking the
+ * pres context to cough up an nsFontMetrics object, which contains
+ * a list of real font handles, one for each font mentioned in
+ * font-family (and for each fallback when we fall off the end of that
+ * list).
+ *
+ * The style system needs to have access to certain metrics, such as
+ * the em height (for the CSS "em" unit), and we use the first Western
+ * font's metrics for that purpose. The platform-specific
+ * implementations are expected to select non-Western fonts that "fit"
+ * reasonably well with the Western font that is loaded at Init time.
+ */
+class nsFontMetrics final {
+ public:
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+
+  enum FontOrientation { eHorizontal, eVertical };
+
+  struct MOZ_STACK_CLASS Params {
+    nsAtom* language = nullptr;
+    bool explicitLanguage = false;
+    FontOrientation orientation = eHorizontal;
+    gfxUserFontSet* userFontSet = nullptr;
+    gfxTextPerfMetrics* textPerf = nullptr;
+    gfxFontFeatureValueSet* featureValueLookup = nullptr;
+  };
+
+  nsFontMetrics(const nsFont& aFont, const Params& aParams,
+                nsPresContext* aContext);
+
+  // Used by stylo
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsFontMetrics)
+
+  /**
+   * Destroy this font metrics. This breaks the association between
+   * the font metrics and the pres context.
+   */
+  void Destroy();
+
+  /**
+   * Return the font's x-height.
+   */
+  nscoord XHeight() const;
+
+  /**
+   * Return the font's cap-height.
+   */
+  nscoord CapHeight() const;
+
+  /**
+   * Return the font's superscript offset (the distance from the
+   * baseline to where a superscript's baseline should be placed).
+   * The value returned will be positive.
+   */
+  nscoord SuperscriptOffset() const;
+
+  /**
+   * Return the font's subscript offset (the distance from the
+   * baseline to where a subscript's baseline should be placed).
+   * The value returned will be positive.
+   */
+  nscoord SubscriptOffset() const;
+
+  /**
+   * Return the font's strikeout offset (the distance from the
+   * baseline to where a strikeout should be placed) and size.
+   * Positive values are above the baseline, negative below.
+   */
+  void GetStrikeout(nscoord& aOffset, nscoord& aSize) const;
+
+  /**
+   * Return the font's underline offset (the distance from the
+   * baseline to where a underline should be placed) and size.
+   * Positive values are above the baseline, negative below.
+   */
+  void GetUnderline(nscoord& aOffset, nscoord& aSize) const;
+
+  /**
+   * Returns the amount of internal leading for the font.
+   * This is normally the difference between the max ascent
+   * and the em ascent.
+   */
+  nscoord InternalLeading() const;
+
+  /**
+   * Returns the amount of external leading for the font.
+   * em ascent(?) plus external leading is the font designer's
+   * recommended line-height for this font.
+   */
+  nscoord ExternalLeading() const;
+
+  /**
+   * Returns the height of the em square.
+   * This is em ascent plus em descent.
+   */
+  nscoord EmHeight() const;
+
+  /**
+   * Returns the ascent part of the em square.
+   */
+  nscoord EmAscent() const;
+
+  /**
+   * Returns the descent part of the em square.
+   */
+  nscoord EmDescent() const;
+
+  /**
+   * Returns the height of the bounding box.
+   * This is max ascent plus max descent.
+   */
+  nscoord MaxHeight() const;
+
+  /**
+   * Returns the maximum distance characters in this font extend
+   * above the base line.
+   */
+  nscoord MaxAscent() const;
+
+  /**
+   * Returns the maximum distance characters in this font extend
+   * below the base line.
+   */
+  nscoord MaxDescent() const;
+
+  /**
+   * Returns the maximum character advance for the font.
+   */
+  nscoord MaxAdvance() const;
+
+  /**
+   * Returns the average character width
+   */
+  nscoord AveCharWidth() const;
+
+  /**
+   * Returns width of the zero character, or AveCharWidth if no zero present.
+   */
+  nscoord ZeroOrAveCharWidth() const;
+
+  /**
+   * Returns the often needed width of the space character
+   */
+  nscoord SpaceWidth() const;
+
+  /**
+   * Returns the font associated with these metrics. The return value
+   * is only defined after Init() has been called.
+   */
+  const nsFont& Font() const { return mFont; }
+
+  /**
+   * Returns the language associated with these metrics
+   */
+  nsAtom* Language() const { return mLanguage; }
+
+  /**
+   * Returns the orientation (horizontal/vertical) of these metrics.
+   */
+  FontOrientation Orientation() const { return mOrientation; }
+
+  int32_t GetMaxStringLength() const;
+
+  // Get the width for this string.  aWidth will be updated with the
+  // width in points, not twips.  Callers must convert it if they
+  // want it in another format.
+  nscoord GetWidth(const char* aString, uint32_t aLength,
+                   DrawTarget* aDrawTarget) const;
+  nscoord GetWidth(const char16_t* aString, uint32_t aLength,
+                   DrawTarget* aDrawTarget) const;
+
+  // Draw a string using this font handle on the surface passed in.
+  void DrawString(const char* aString, uint32_t aLength, nscoord aX, nscoord aY,
+                  gfxContext* aContext) const;
+  void DrawString(const char16_t* aString, uint32_t aLength, nscoord aX,
+                  nscoord aY, gfxContext* aContext,
+                  DrawTarget* aTextRunConstructionDrawTarget) const;
+
+  nsBoundingMetrics GetBoundingMetrics(const char16_t* aString,
+                                       uint32_t aLength,
+                                       DrawTarget* aDrawTarget) const;
+
+  // Returns the LOOSE_INK_EXTENTS bounds of the text for determing the
+  // overflow area of the string.
+  nsBoundingMetrics GetInkBoundsForInkOverflow(const char16_t* aString,
+                                               uint32_t aLength,
+                                               DrawTarget* aDrawTarget) const;
+
+  void SetTextRunRTL(bool aIsRTL) { mTextRunRTL = aIsRTL; }
+  bool GetTextRunRTL() const { return mTextRunRTL; }
+
+  void SetVertical(bool aVertical) { mVertical = aVertical; }
+  bool GetVertical() const { return mVertical; }
+
+  void SetTextOrientation(mozilla::StyleTextOrientation aTextOrientation) {
+    mTextOrientation = aTextOrientation;
+  }
+  mozilla::StyleTextOrientation GetTextOrientation() const {
+    return mTextOrientation;
+  }
+
+  bool ExplicitLanguage() const { return mExplicitLanguage; }
+
+  gfxFontGroup* GetThebesFontGroup() const { return mFontGroup; }
+  gfxUserFontSet* GetUserFontSet() const;
+
+  int32_t AppUnitsPerDevPixel() const { return mP2A; }
+
+ private:
+  // Private destructor, to discourage deletion outside of Release():
+  ~nsFontMetrics();
+
+  const nsFont mFont;
+  RefPtr<gfxFontGroup> mFontGroup;
+  RefPtr<nsAtom> const mLanguage;
+  // Pointer to the pres context for which this fontMetrics object was
+  // created.
+  nsPresContext* MOZ_NON_OWNING_REF mPresContext;
+  const int32_t mP2A;
+
+  // The font orientation (horizontal or vertical) for which these metrics
+  // have been initialized. This determines which line metrics (ascent and
+  // descent) they will return.
+  const FontOrientation mOrientation;
+
+  // Whether mLanguage comes from explicit markup (in which case it should be
+  // used to tailor effects like case-conversion) or is an inferred/default
+  // value.
+  const bool mExplicitLanguage;
+
+  // These fields may be set by clients to control the behavior of methods
+  // like GetWidth and DrawString according to the writing mode, direction
+  // and text-orientation desired.
+  bool mTextRunRTL;
+  bool mVertical;
+  mozilla::StyleTextOrientation mTextOrientation;
+};
+
+#endif /* NSFONTMETRICS__H__ */
diff --git a/gfx/src/nsGfxCIID.h b/gfx/src/nsGfxCIID.h
new file mode 100644
index 0000000000..65f09ed47b
--- /dev/null
+++ b/gfx/src/nsGfxCIID.h
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsGfxCIID_h__
+#define nsGfxCIID_h__
+
+#define NS_FONT_ENUMERATOR_CID                       \
+  {                                                  \
+    0xa6cf9115, 0x15b3, 0x11d2, {                    \
+      0x93, 0x2e, 0x00, 0x80, 0x5f, 0x8a, 0xdd, 0x32 \
+    }                                                \
+  }
+
+#define NS_SCRIPTABLE_REGION_CID                     \
+  {                                                  \
+    0xda5b130a, 0x1dd1, 0x11b2, {                    \
+      0xad, 0x47, 0xf4, 0x55, 0xb1, 0x81, 0x4a, 0x78 \
+    }                                                \
+  }
+
+#define NS_GFX_INITIALIZATION_CID                    \
+  {                                                  \
+    0x67c41576, 0x9664, 0x4ed5, {                    \
+      0x90, 0xc1, 0xf6, 0x68, 0x3f, 0xd5, 0x2c, 0x8f \
+    }                                                \
+  }
+
+#endif
diff --git a/gfx/src/nsIFontEnumerator.idl b/gfx/src/nsIFontEnumerator.idl
new file mode 100644
index 0000000000..5c6177f39f
--- /dev/null
+++ b/gfx/src/nsIFontEnumerator.idl
@@ -0,0 +1,72 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(924d98d9-3518-4cb4-8708-c74fe8e3ec3c)]
+interface nsIFontEnumerator : nsISupports
+{
+  /**
+   * Return a sorted array of the names of all installed fonts.
+   *
+   * @return array of names
+   * @return void
+   */
+  Array<AString> EnumerateAllFonts();
+
+  /**
+   * Return a sorted array of names of fonts that support the given language
+   * group and are suitable for use as the given CSS generic font.
+   *
+   * @param  aLangGroup language group
+   * @param  aGeneric   CSS generic font
+   * @return            array of names
+   * @return void
+   */
+  Array<AString> EnumerateFonts(in string aLangGroup, in string aGeneric);
+
+  /**
+   * Return a promise that resolves to a sorted array of the names of all
+   * installed fonts.
+   *
+   * @return Promise that resolves to Array
+   */
+  [implicit_jscontext]
+  jsval EnumerateAllFontsAsync();
+
+  /**
+   * Return a promise that resolves to a sorted array of names of fonts
+   * that support the given language group and are suitable for use as the given
+   * CSS generic font.
+   *
+   * @param  aLangGroup language group
+   * @param  aGeneric   CSS generic font
+   * @return Promise that resolves to Array
+   */
+  [implicit_jscontext]
+  jsval EnumerateFontsAsync(in string aLangGroup, in string aGeneric);
+
+  /**
+    @param  aLangGroup language group
+    @return bool do we have a font for this language group
+   */
+  void HaveFontFor(in string aLangGroup, [retval] out boolean aResult);
+
+  /**
+   * @param  aLangGroup language group
+   * @param  aGeneric CSS generic font
+   * @return suggested default font for this language group and generic family
+   */
+  wstring getDefaultFont(in string aLangGroup, in string aGeneric);
+
+  /**
+   * get the standard family name on the system from given family
+   * @param  aName family name which may be alias
+   * @return the standard family name on the system, if given name does not
+   *         exist, returns empty string
+   */
+  wstring getStandardFamilyName(in wstring aName);
+};
diff --git a/gfx/src/nsITheme.h b/gfx/src/nsITheme.h
new file mode 100644
index 0000000000..92a4800be6
--- /dev/null
+++ b/gfx/src/nsITheme.h
@@ -0,0 +1,271 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* service providing platform-specific native rendering for widgets */
+
+#ifndef nsITheme_h_
+#define nsITheme_h_
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "nsISupports.h"
+#include "nsID.h"
+#include "nscore.h"
+#include "Units.h"
+
+struct nsRect;
+class gfxContext;
+class nsAttrValue;
+class nsPresContext;
+class nsDeviceContext;
+class nsIFrame;
+class nsAtom;
+class nsIWidget;
+
+namespace mozilla {
+class ComputedStyle;
+enum class StyleAppearance : uint8_t;
+enum class StyleScrollbarWidth : uint8_t;
+namespace layers {
+class StackingContextHelper;
+class RenderRootStateManager;
+}  // namespace layers
+namespace widget {
+class Theme;
+}  // namespace widget
+namespace wr {
+class DisplayListBuilder;
+class IpcResourceUpdateQueue;
+}  // namespace wr
+}  // namespace mozilla
+
+// IID for the nsITheme interface
+// {7329f760-08cb-450f-8225-dae729096dec}
+#define NS_ITHEME_IID                                \
+  {                                                  \
+    0x7329f760, 0x08cb, 0x450f, {                    \
+      0x82, 0x25, 0xda, 0xe7, 0x29, 0x09, 0x6d, 0xec \
+    }                                                \
+  }
+
+/**
+ * nsITheme is a service that provides platform-specific native
+ * rendering for widgets.  In other words, it provides the necessary
+ * operations to draw a rendering object (an nsIFrame) as a native
+ * widget.
+ *
+ * All the methods on nsITheme take a rendering context or device
+ * context, a frame (the rendering object), and a widget type (one of
+ * the constants in nsThemeConstants.h).
+ */
+class nsITheme : public nsISupports {
+ protected:
+  using LayoutDeviceIntMargin = mozilla::LayoutDeviceIntMargin;
+  using LayoutDeviceIntSize = mozilla::LayoutDeviceIntSize;
+  using LayoutDeviceIntCoord = mozilla::LayoutDeviceIntCoord;
+  using StyleAppearance = mozilla::StyleAppearance;
+  using StyleScrollbarWidth = mozilla::StyleScrollbarWidth;
+  using ComputedStyle = mozilla::ComputedStyle;
+
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ITHEME_IID)
+
+  /**
+   * Draw the actual theme background.
+   * @param aContext the context to draw into
+   * @param aFrame the frame for the widget that we're drawing
+   * @param aWidgetType the -moz-appearance value to draw
+   * @param aRect the rectangle defining the area occupied by the widget
+   * @param aDirtyRect the rectangle that needs to be drawn
+   * @param DrawOverflow whether outlines, shadows and other such overflowing
+   *        things should be drawn. Honoring this creates better results for
+   *        box-shadow, though it's not a hard requirement.
+   */
+  enum class DrawOverflow { No, Yes };
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                  StyleAppearance aWidgetType,
+                                  const nsRect& aRect, const nsRect& aDirtyRect,
+                                  DrawOverflow = DrawOverflow::Yes) = 0;
+
+  /**
+   * Create WebRender commands for the theme background.
+   * @return true if the theme knows how to create WebRender commands for the
+   *         given widget type, false if DrawWidgetBackground need sto be called
+   *         instead.
+   */
+  virtual bool CreateWebRenderCommandsForWidget(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const mozilla::layers::StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+      StyleAppearance aWidgetType, const nsRect& aRect) {
+    return false;
+  }
+
+  /**
+   * Returns the minimum widths of a scrollbar for a given style, that is, the
+   * minimum width for a vertical scrollbar, and the minimum height of a
+   * horizontal scrollbar.
+   */
+  enum class Overlay { No, Yes };
+  virtual LayoutDeviceIntCoord GetScrollbarSize(const nsPresContext*,
+                                                StyleScrollbarWidth,
+                                                Overlay) = 0;
+
+  /**
+   * Return the border for the widget, in device pixels.
+   */
+  [[nodiscard]] virtual LayoutDeviceIntMargin GetWidgetBorder(
+      nsDeviceContext* aContext, nsIFrame* aFrame,
+      StyleAppearance aWidgetType) = 0;
+
+  /**
+   * This method can return false to indicate that the CSS padding
+   * value should be used.  Otherwise, it will fill in aResult with the
+   * computed padding, in pixels, and return true.
+   *
+   * XXXldb This ought to be required to return true for non-containers
+   * so that we don't let specified padding that has no effect change
+   * the computed padding and potentially the size.
+   */
+  virtual bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
+                                StyleAppearance aWidgetType,
+                                LayoutDeviceIntMargin* aResult) = 0;
+
+  /**
+   * On entry, *aResult is positioned at 0,0 and sized to the new size
+   * of aFrame (aFrame->GetSize() may be stale and should not be used).
+   * This method can return false to indicate that no special
+   * overflow area is required by the native widget. Otherwise it will
+   * fill in aResult with the desired overflow area, in appunits, relative
+   * to the frame origin, and return true.
+   *
+   * This overflow area is used to determine what area needs to be
+   * repainted when the widget changes.  However, it does not affect the
+   * widget's size or what area is reachable by scrollbars.  (In other
+   * words, in layout terms, it affects ink overflow but not
+   * scrollable overflow.)
+   */
+  virtual bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
+                                 StyleAppearance aWidgetType,
+                                 /*INOUT*/ nsRect* aOverflowRect) {
+    return false;
+  }
+
+  /**
+   * Get the preferred content-box size of a checkbox / radio button, in app
+   * units.  Historically 9px.
+   */
+  virtual nscoord GetCheckboxRadioPrefSize() {
+    return mozilla::CSSPixel::ToAppUnits(9);
+  }
+
+  /**
+   * Get the minimum border-box size of a widget, in device pixels.
+   */
+  virtual mozilla::LayoutDeviceIntSize GetMinimumWidgetSize(
+      nsPresContext* aPresContext, nsIFrame* aFrame,
+      StyleAppearance aWidgetType) = 0;
+
+  enum Transparency { eOpaque = 0, eTransparent, eUnknownTransparency };
+
+  /**
+   * Returns what we know about the transparency of the widget.
+   */
+  virtual Transparency GetWidgetTransparency(nsIFrame* aFrame,
+                                             StyleAppearance aWidgetType) {
+    return eUnknownTransparency;
+  }
+
+  /**
+   * Sets |*aShouldRepaint| to indicate whether an attribute or content state
+   * change should trigger a repaint.  Call with null |aAttribute| (and
+   * null |aOldValue|) for content state changes.
+   */
+  NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, StyleAppearance aWidgetType,
+                                nsAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) = 0;
+
+  NS_IMETHOD ThemeChanged() = 0;
+
+  virtual bool WidgetAppearanceDependsOnWindowFocus(
+      StyleAppearance aWidgetType) {
+    return false;
+  }
+
+  /**
+   * ThemeGeometryType values are used for describing themed nsIFrames in
+   * calls to nsIWidget::UpdateThemeGeometries. We don't simply pass the
+   * -moz-appearance value ("widget type") of the frame because the widget may
+   * want to treat different frames with the same -moz-appearance differently
+   * based on other properties of the frame. So we give the theme a first look
+   * at the frame in nsITheme::ThemeGeometryTypeForWidget and pass the
+   * returned ThemeGeometryType along to the widget.
+   * Each theme backend defines the ThemeGeometryType values it needs in its
+   * own nsITheme subclass. eThemeGeometryTypeUnknown is the only value that's
+   * shared between backends.
+   */
+  typedef uint8_t ThemeGeometryType;
+  enum { eThemeGeometryTypeUnknown = 0 };
+
+  /**
+   * Returns the theme geometry type that should be used in the ThemeGeometry
+   * array that's passed to the widget using nsIWidget::UpdateThemeGeometries.
+   * A return value of eThemeGeometryTypeUnknown means that this frame will
+   * not be included in the ThemeGeometry array.
+   */
+  virtual ThemeGeometryType ThemeGeometryTypeForWidget(
+      nsIFrame* aFrame, StyleAppearance aWidgetType) {
+    return eThemeGeometryTypeUnknown;
+  }
+
+  /**
+   * Can the nsITheme implementation handle this widget?
+   */
+  virtual bool ThemeSupportsWidget(nsPresContext* aPresContext,
+                                   nsIFrame* aFrame,
+                                   StyleAppearance aWidgetType) = 0;
+
+  virtual bool WidgetIsContainer(StyleAppearance aWidgetType) = 0;
+
+  /**
+   * Does the nsITheme implementation draw its own focus ring for this widget?
+   */
+  virtual bool ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) = 0;
+
+  /**
+   * Whether we want an inner focus ring for buttons and such.
+   *
+   * Usually, we don't want it if we have our own focus indicators, but windows
+   * is special, because it wants it even though focus also alters the border
+   * color and such.
+   */
+  virtual bool ThemeWantsButtonInnerFocusRing(nsIFrame* aFrame,
+                                              StyleAppearance aAppearance) {
+    return !ThemeDrawsFocusForWidget(aFrame, aAppearance);
+  }
+
+  /**
+   * Should we insert a dropmarker inside of combobox button?
+   */
+  virtual bool ThemeNeedsComboboxDropmarker() = 0;
+
+  virtual bool ThemeSupportsScrollbarButtons() = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsITheme, NS_ITHEME_IID)
+
+// Singleton accessor functions, these should never return null.
+//
+// Do not use directly, use nsPresContext::Theme instead.
+extern already_AddRefed<nsITheme> do_GetNativeThemeDoNotUseDirectly();
+extern already_AddRefed<nsITheme> do_GetBasicNativeThemeDoNotUseDirectly();
+extern already_AddRefed<nsITheme> do_GetRDMThemeDoNotUseDirectly();
+
+// Native theme creation function, these should never return null.
+extern already_AddRefed<mozilla::widget::Theme>
+do_CreateNativeThemeDoNotUseDirectly();
+
+#endif
diff --git a/gfx/src/nsMargin.h b/gfx/src/nsMargin.h
new file mode 100644
index 0000000000..cf05894ff3
--- /dev/null
+++ b/gfx/src/nsMargin.h
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSMARGIN_H
+#define NSMARGIN_H
+
+#include "nsCoord.h"
+#include "mozilla/gfx/BaseMargin.h"
+#include "mozilla/gfx/Rect.h"
+
+struct nsMargin : public mozilla::gfx::BaseMargin<nscoord, nsMargin> {
+  typedef mozilla::gfx::BaseMargin<nscoord, nsMargin> Super;
+
+  // Constructors
+  nsMargin() = default;
+  nsMargin(const nsMargin& aMargin) = default;
+  nsMargin(nscoord aTop, nscoord aRight, nscoord aBottom, nscoord aLeft)
+      : Super(aTop, aRight, aBottom, aLeft) {}
+};
+
+typedef mozilla::gfx::IntMargin nsIntMargin;
+
+#endif /* NSMARGIN_H */
diff --git a/gfx/src/nsPoint.h b/gfx/src/nsPoint.h
new file mode 100644
index 0000000000..86688d2142
--- /dev/null
+++ b/gfx/src/nsPoint.h
@@ -0,0 +1,95 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSPOINT_H
+#define NSPOINT_H
+
+#include <cstdint>
+#include "nsCoord.h"
+#include "mozilla/gfx/BasePoint.h"
+#include "mozilla/gfx/Point.h"
+
+// nsIntPoint represents a point in one of the types of pixels.
+// Uses of nsIntPoint should eventually be converted to CSSIntPoint,
+// LayoutDeviceIntPoint, etc. (see layout/base/Units.h).
+typedef mozilla::gfx::IntPoint nsIntPoint;
+
+// nsPoint represents a point in app units.
+
+struct nsPoint : public mozilla::gfx::BasePoint<nscoord, nsPoint> {
+  typedef mozilla::gfx::BasePoint<nscoord, nsPoint> Super;
+
+  nsPoint() = default;
+  nsPoint(const nsPoint& aPoint) = default;
+  nsPoint(nscoord aX, nscoord aY) : Super(aX, aY) {}
+
+  inline nsIntPoint ScaleToNearestPixels(float aXScale, float aYScale,
+                                         nscoord aAppUnitsPerPixel) const;
+  inline nsIntPoint ToNearestPixels(nscoord aAppUnitsPerPixel) const;
+
+  /**
+   * Return this point scaled to a different appunits per pixel (APP) ratio.
+   * @param aFromAPP the APP to scale from
+   * @param aToAPP the APP to scale to
+   */
+  [[nodiscard]] inline nsPoint ScaleToOtherAppUnits(int32_t aFromAPP,
+                                                    int32_t aToAPP) const;
+
+  [[nodiscard]] inline nsPoint RemoveResolution(const float resolution) const;
+  [[nodiscard]] inline nsPoint ApplyResolution(const float resolution) const;
+};
+
+inline nsPoint ToAppUnits(const nsIntPoint& aPoint, nscoord aAppUnitsPerPixel);
+
+inline nsIntPoint nsPoint::ScaleToNearestPixels(
+    float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const {
+  return nsIntPoint(
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(x, aAppUnitsPerPixel) * aXScale),
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(y, aAppUnitsPerPixel) * aYScale));
+}
+
+inline nsIntPoint nsPoint::ToNearestPixels(nscoord aAppUnitsPerPixel) const {
+  return ScaleToNearestPixels(1.0f, 1.0f, aAppUnitsPerPixel);
+}
+
+inline nsPoint nsPoint::ScaleToOtherAppUnits(int32_t aFromAPP,
+                                             int32_t aToAPP) const {
+  if (aFromAPP != aToAPP) {
+    nsPoint point;
+    point.x = NSToCoordRound(NSCoordScale(x, aFromAPP, aToAPP));
+    point.y = NSToCoordRound(NSCoordScale(y, aFromAPP, aToAPP));
+    return point;
+  }
+  return *this;
+}
+
+inline nsPoint nsPoint::RemoveResolution(const float resolution) const {
+  if (resolution != 1.0f) {
+    nsPoint point;
+    point.x = NSToCoordRound(NSCoordToFloat(x) / resolution);
+    point.y = NSToCoordRound(NSCoordToFloat(y) / resolution);
+    return point;
+  }
+  return *this;
+}
+
+inline nsPoint nsPoint::ApplyResolution(const float resolution) const {
+  if (resolution != 1.0f) {
+    nsPoint point;
+    point.x = NSToCoordRound(NSCoordToFloat(x) * resolution);
+    point.y = NSToCoordRound(NSCoordToFloat(y) * resolution);
+    return point;
+  }
+  return *this;
+}
+
+// app units are integer multiples of pixels, so no rounding needed
+inline nsPoint ToAppUnits(const nsIntPoint& aPoint, nscoord aAppUnitsPerPixel) {
+  return nsPoint(NSIntPixelsToAppUnits(aPoint.x, aAppUnitsPerPixel),
+                 NSIntPixelsToAppUnits(aPoint.y, aAppUnitsPerPixel));
+}
+
+#endif /* NSPOINT_H */
diff --git a/gfx/src/nsRect.cpp b/gfx/src/nsRect.cpp
new file mode 100644
index 0000000000..8f88c9190e
--- /dev/null
+++ b/gfx/src/nsRect.cpp
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsRect.h"
+#include "mozilla/gfx/Types.h"   // for eSideBottom, etc
+#include "mozilla/CheckedInt.h"  // for CheckedInt
+#include "nsDeviceContext.h"     // for nsDeviceContext
+#include "nsString.h"            // for nsAutoString, etc
+#include "nsMargin.h"            // for nsMargin
+
+static_assert(
+    (int(mozilla::eSideTop) == 0) && (int(mozilla::eSideRight) == 1) &&
+        (int(mozilla::eSideBottom) == 2) && (int(mozilla::eSideLeft) == 3),
+    "The mozilla::Side sequence must match the nsMargin nscoord sequence");
+
+const mozilla::gfx::IntRect& GetMaxSizedIntRect() {
+  static const mozilla::gfx::IntRect r(0, 0, INT32_MAX, INT32_MAX);
+  return r;
+}
+
+bool nsRect::Overflows() const {
+  mozilla::CheckedInt<int32_t> xMost = this->x;
+  xMost += this->width;
+  mozilla::CheckedInt<int32_t> yMost = this->y;
+  yMost += this->height;
+  return !xMost.isValid() || !yMost.isValid();
+}
diff --git a/gfx/src/nsRect.h b/gfx/src/nsRect.h
new file mode 100644
index 0000000000..91c2c7a428
--- /dev/null
+++ b/gfx/src/nsRect.h
@@ -0,0 +1,478 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSRECT_H
+#define NSRECT_H
+
+#include <stdint.h>          // for int32_t, int64_t
+#include <algorithm>         // for min/max
+#include "mozilla/Likely.h"  // for MOZ_UNLIKELY
+#include "mozilla/gfx/BaseRect.h"
+#include "mozilla/gfx/Rect.h"
+#include "nsCoord.h"      // for nscoord, etc
+#include "nsISupports.h"  // for MOZ_COUNT_CTOR, etc
+#include "nsPoint.h"      // for nsIntPoint, nsPoint
+#include "nsSize.h"       // for IntSize, nsSize
+#if !defined(ANDROID) && (defined(__SSE2__) || defined(_M_X64) || \
+                          (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
+#  if defined(_MSC_VER) && !defined(__clang__)
+#    include "smmintrin.h"
+#  else
+#    include "emmintrin.h"
+#  endif
+#endif
+
+struct nsMargin;
+
+typedef mozilla::gfx::IntRect nsIntRect;
+
+struct nsRect : public mozilla::gfx::BaseRect<nscoord, nsRect, nsPoint, nsSize,
+                                              nsMargin> {
+  typedef mozilla::gfx::BaseRect<nscoord, nsRect, nsPoint, nsSize, nsMargin>
+      Super;
+
+  // Constructors
+  nsRect() : Super() { MOZ_COUNT_CTOR(nsRect); }
+  nsRect(const nsRect& aRect) : Super(aRect) { MOZ_COUNT_CTOR(nsRect); }
+  nsRect(const nsPoint& aOrigin, const nsSize& aSize) : Super(aOrigin, aSize) {
+    MOZ_COUNT_CTOR(nsRect);
+  }
+  nsRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+      : Super(aX, aY, aWidth, aHeight) {
+    MOZ_COUNT_CTOR(nsRect);
+  }
+  nsRect& operator=(const nsRect&) = default;
+
+  MOZ_COUNTED_DTOR(nsRect)
+
+  // We have saturating versions of all the Union methods. These avoid
+  // overflowing nscoord values in the 'width' and 'height' fields by
+  // clamping the width and height values to nscoord_MAX if necessary.
+
+  // Returns the smallest rectangle that contains both the area of both
+  // this and aRect. Thus, empty input rectangles are ignored.
+  // Note: if both rectangles are empty, returns aRect.
+  [[nodiscard]] nsRect SaturatingUnion(const nsRect& aRect) const {
+    if (IsEmpty()) {
+      return aRect;
+    } else if (aRect.IsEmpty()) {
+      return *static_cast<const nsRect*>(this);
+    } else {
+      return SaturatingUnionEdges(aRect);
+    }
+  }
+
+  [[nodiscard]] nsRect SaturatingUnionEdges(const nsRect& aRect) const {
+    nscoord resultX = std::min(aRect.X(), x);
+    int64_t w =
+        std::max(int64_t(aRect.X()) + aRect.Width(), int64_t(x) + width) -
+        resultX;
+    if (MOZ_UNLIKELY(w > nscoord_MAX)) {
+      // Clamp huge negative x to nscoord_MIN / 2 and try again.
+      resultX = std::max(resultX, nscoord_MIN / 2);
+      w = std::max(int64_t(aRect.X()) + aRect.Width(), int64_t(x) + width) -
+          resultX;
+      if (MOZ_UNLIKELY(w > nscoord_MAX)) {
+        w = nscoord_MAX;
+      }
+    }
+
+    nscoord resultY = std::min(aRect.y, y);
+    int64_t h =
+        std::max(int64_t(aRect.Y()) + aRect.Height(), int64_t(y) + height) -
+        resultY;
+    if (MOZ_UNLIKELY(h > nscoord_MAX)) {
+      // Clamp huge negative y to nscoord_MIN / 2 and try again.
+      resultY = std::max(resultY, nscoord_MIN / 2);
+      h = std::max(int64_t(aRect.Y()) + aRect.Height(), int64_t(y) + height) -
+          resultY;
+      if (MOZ_UNLIKELY(h > nscoord_MAX)) {
+        h = nscoord_MAX;
+      }
+    }
+    return nsRect(resultX, resultY, nscoord(w), nscoord(h));
+  }
+
+  // Make all nsRect Union methods be saturating.
+  [[nodiscard]] nsRect UnionEdges(const nsRect& aRect) const {
+    return SaturatingUnionEdges(aRect);
+  }
+  [[nodiscard]] nsRect Union(const nsRect& aRect) const {
+    return SaturatingUnion(aRect);
+  }
+  [[nodiscard]] nsRect UnsafeUnion(const nsRect& aRect) const {
+    return Super::Union(aRect);
+  }
+  void UnionRect(const nsRect& aRect1, const nsRect& aRect2) {
+    *this = aRect1.Union(aRect2);
+  }
+
+#if defined(_MSC_VER) && !defined(__clang__) && \
+    (defined(_M_X64) || defined(_M_IX86))
+  // Only MSVC supports inlining intrinsics for archs you're not compiling for.
+  [[nodiscard]] nsRect Intersect(const nsRect& aRect) const {
+    nsRect result;
+    if (mozilla::gfx::Factory::HasSSE4()) {
+      __m128i rect1 = _mm_loadu_si128((__m128i*)&aRect);  // x1, y1, w1, h1
+      __m128i rect2 = _mm_loadu_si128((__m128i*)this);    // x2, y2, w2, h2
+
+      __m128i resultRect = _mm_max_epi32(rect1, rect2);  // xr, yr, zz, zz
+
+      // result.width = std::min<int32_t>(x - result.x + width,
+      //                                  aRect.x - result.x + aRect.width);
+      // result.height = std::min<int32_t>(y - result.y + height,
+      //                                   aRect.y - result.y + aRect.height);
+      __m128i widthheight = _mm_min_epi32(
+          _mm_add_epi32(_mm_sub_epi32(rect1, resultRect),
+                        _mm_srli_si128(rect1, 8)),
+          _mm_add_epi32(_mm_sub_epi32(rect2, resultRect),
+                        _mm_srli_si128(rect2, 8)));  // w, h, zz, zz
+      widthheight = _mm_slli_si128(widthheight, 8);  // 00, 00, wr, hr
+
+      resultRect =
+          _mm_blend_epi16(resultRect, widthheight, 0xF0);  // xr, yr, wr, hr
+
+      if ((_mm_movemask_ps(_mm_castsi128_ps(
+               _mm_cmplt_epi32(resultRect, _mm_setzero_si128()))) &
+           0xC) != 0) {
+        // It's potentially more efficient to store all 0s. But the non SSE4
+        // code leaves x/y intact so let's do the same here.
+        resultRect = _mm_and_si128(resultRect,
+                                   _mm_set_epi32(0, 0, 0xFFFFFFFF, 0xFFFFFFFF));
+      }
+
+      _mm_storeu_si128((__m128i*)&result, resultRect);
+
+      return result;
+    }
+
+    result.x = std::max<int32_t>(x, aRect.x);
+    result.y = std::max<int32_t>(y, aRect.y);
+    result.width = std::min<int32_t>(x - result.x + width,
+                                     aRect.x - result.x + aRect.width);
+    result.height = std::min<int32_t>(y - result.y + height,
+                                      aRect.y - result.y + aRect.height);
+    if (result.width < 0 || result.height < 0) {
+      result.SizeTo(0, 0);
+    }
+    return result;
+  }
+
+  bool IntersectRect(const nsRect& aRect1, const nsRect& aRect2) {
+    if (mozilla::gfx::Factory::HasSSE4()) {
+      __m128i rect1 = _mm_loadu_si128((__m128i*)&aRect1);  // x1, y1, w1, h1
+      __m128i rect2 = _mm_loadu_si128((__m128i*)&aRect2);  // x2, y2, w2, h2
+
+      __m128i resultRect = _mm_max_epi32(rect1, rect2);  // xr, yr, zz, zz
+      // result.width = std::min<int32_t>(x - result.x + width,
+      //                                  aRect.x - result.x + aRect.width);
+      // result.height = std::min<int32_t>(y - result.y + height,
+      //                                   aRect.y - result.y + aRect.height);
+      __m128i widthheight = _mm_min_epi32(
+          _mm_add_epi32(_mm_sub_epi32(rect1, resultRect),
+                        _mm_srli_si128(rect1, 8)),
+          _mm_add_epi32(_mm_sub_epi32(rect2, resultRect),
+                        _mm_srli_si128(rect2, 8)));  // w, h, zz, zz
+      widthheight = _mm_slli_si128(widthheight, 8);  // 00, 00, wr, hr
+
+      resultRect =
+          _mm_blend_epi16(resultRect, widthheight, 0xF0);  // xr, yr, wr, hr
+
+      if ((_mm_movemask_ps(_mm_castsi128_ps(
+               _mm_cmpgt_epi32(resultRect, _mm_setzero_si128()))) &
+           0xC) != 0xC) {
+        // It's potentially more efficient to store all 0s. But the non SSE4
+        // code leaves x/y intact so let's do the same here.
+        resultRect = _mm_and_si128(resultRect,
+                                   _mm_set_epi32(0, 0, 0xFFFFFFFF, 0xFFFFFFFF));
+        _mm_storeu_si128((__m128i*)this, resultRect);
+        return false;
+      }
+
+      _mm_storeu_si128((__m128i*)this, resultRect);
+
+      return true;
+    }
+
+    int32_t newX = std::max<int32_t>(aRect1.x, aRect2.x);
+    int32_t newY = std::max<int32_t>(aRect1.y, aRect2.y);
+    width = std::min<int32_t>(aRect1.x - newX + aRect1.width,
+                              aRect2.x - newX + aRect2.width);
+    height = std::min<int32_t>(aRect1.y - newY + aRect1.height,
+                               aRect2.y - newY + aRect2.height);
+    x = newX;
+    y = newY;
+    if (width <= 0 || height <= 0) {
+      SizeTo(0, 0);
+      return false;
+    }
+    return true;
+  }
+#endif
+
+  // Return whether this rect's right or bottom edge overflow int32.
+  bool Overflows() const;
+
+  /**
+   * Return this rect scaled to a different appunits per pixel (APP) ratio.
+   * In the RoundOut version we make the rect the smallest rect containing the
+   * unrounded result. In the RoundIn version we make the rect the largest rect
+   * contained in the unrounded result.
+   * @param aFromAPP the APP to scale from
+   * @param aToAPP the APP to scale to
+   * @note this can turn an empty rectangle into a non-empty rectangle
+   */
+  [[nodiscard]] inline nsRect ScaleToOtherAppUnitsRoundOut(
+      int32_t aFromAPP, int32_t aToAPP) const;
+  [[nodiscard]] inline nsRect ScaleToOtherAppUnitsRoundIn(int32_t aFromAPP,
+                                                          int32_t aToAPP) const;
+
+  [[nodiscard]] inline mozilla::gfx::IntRect ScaleToNearestPixels(
+      float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const;
+
+  [[nodiscard]] inline mozilla::gfx::IntRect ToNearestPixels(
+      nscoord aAppUnitsPerPixel) const;
+
+  // Note: this can turn an empty rectangle into a non-empty rectangle
+  [[nodiscard]] inline mozilla::gfx::IntRect ScaleToOutsidePixels(
+      float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const;
+
+  // Note: this can turn an empty rectangle into a non-empty rectangle
+  [[nodiscard]] inline mozilla::gfx::IntRect ToOutsidePixels(
+      nscoord aAppUnitsPerPixel) const;
+
+  [[nodiscard]] inline mozilla::gfx::IntRect ScaleToInsidePixels(
+      float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const;
+
+  [[nodiscard]] inline mozilla::gfx::IntRect ToInsidePixels(
+      nscoord aAppUnitsPerPixel) const;
+
+  // This is here only to keep IPDL-generated code happy. DO NOT USE.
+  bool operator==(const nsRect& aRect) const { return IsEqualEdges(aRect); }
+
+  [[nodiscard]] inline nsRect RemoveResolution(const float aResolution) const;
+};
+
+/*
+ * App Unit/Pixel conversions
+ */
+
+inline nsRect nsRect::ScaleToOtherAppUnitsRoundOut(int32_t aFromAPP,
+                                                   int32_t aToAPP) const {
+  if (aFromAPP == aToAPP) {
+    return *this;
+  }
+
+  nsRect rect;
+  rect.SetBox(NSToCoordFloor(NSCoordScale(x, aFromAPP, aToAPP)),
+              NSToCoordFloor(NSCoordScale(y, aFromAPP, aToAPP)),
+              NSToCoordCeil(NSCoordScale(XMost(), aFromAPP, aToAPP)),
+              NSToCoordCeil(NSCoordScale(YMost(), aFromAPP, aToAPP)));
+  return rect;
+}
+
+inline nsRect nsRect::ScaleToOtherAppUnitsRoundIn(int32_t aFromAPP,
+                                                  int32_t aToAPP) const {
+  if (aFromAPP == aToAPP) {
+    return *this;
+  }
+
+  nsRect rect;
+  rect.SetBox(NSToCoordCeil(NSCoordScale(x, aFromAPP, aToAPP)),
+              NSToCoordCeil(NSCoordScale(y, aFromAPP, aToAPP)),
+              NSToCoordFloor(NSCoordScale(XMost(), aFromAPP, aToAPP)),
+              NSToCoordFloor(NSCoordScale(YMost(), aFromAPP, aToAPP)));
+  return rect;
+}
+
+#if !defined(ANDROID) && (defined(__SSE2__) || defined(_M_X64) || \
+                          (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
+// Life would be so much better if we had SSE4 here.
+static MOZ_ALWAYS_INLINE __m128i floor_ps2epi32(__m128 x) {
+  __m128 one = _mm_set_ps(1.0f, 1.0f, 1.0f, 1.0f);
+
+  __m128 t = _mm_cvtepi32_ps(_mm_cvttps_epi32(x));
+  __m128 r = _mm_sub_ps(t, _mm_and_ps(_mm_cmplt_ps(x, t), one));
+
+  return _mm_cvttps_epi32(r);
+}
+
+static MOZ_ALWAYS_INLINE __m128i ceil_ps2epi32(__m128 x) {
+  __m128 t = _mm_sub_ps(_mm_setzero_ps(), x);
+  __m128i r = _mm_sub_epi32(_mm_setzero_si128(), floor_ps2epi32(t));
+
+  return r;
+}
+#endif
+
+// scale the rect but round to preserve centers
+inline mozilla::gfx::IntRect nsRect::ScaleToNearestPixels(
+    float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const {
+  mozilla::gfx::IntRect rect;
+  // Android x86 builds have bindgen issues.
+#if !defined(ANDROID) && (defined(__SSE2__) || defined(_M_X64) || \
+                          (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
+  __m128 appUnitsPacked = _mm_set_ps(aAppUnitsPerPixel, aAppUnitsPerPixel,
+                                     aAppUnitsPerPixel, aAppUnitsPerPixel);
+  __m128 scalesPacked = _mm_set_ps(aYScale, aXScale, aYScale, aXScale);
+  __m128 biasesPacked = _mm_set_ps(0.5f, 0.5f, 0.5f, 0.5f);
+
+  __m128i rectPacked = _mm_loadu_si128((__m128i*)this);
+  __m128i topLeft = _mm_slli_si128(rectPacked, 8);
+
+  rectPacked = _mm_add_epi32(rectPacked, topLeft);  // X, Y, XMost(), YMost()
+
+  __m128 rectFloat = _mm_cvtepi32_ps(rectPacked);
+
+  // Scale, i.e. ([ x y xmost ymost ] / aAppUnitsPerPixel) * [ aXScale aYScale
+  // aXScale aYScale ]
+  rectFloat = _mm_mul_ps(_mm_div_ps(rectFloat, appUnitsPacked), scalesPacked);
+
+  // Floor
+  // Executed with bias and roundmode down, since round-nearest rounds 0.5
+  // downward half the time.
+  rectFloat = _mm_add_ps(rectFloat, biasesPacked);
+  rectPacked = floor_ps2epi32(rectFloat);
+
+  topLeft = _mm_slli_si128(rectPacked, 8);
+  rectPacked = _mm_sub_epi32(rectPacked, topLeft);  // X, Y, Width, Height
+
+  // Avoid negative width/height due to overflow.
+  __m128i mask = _mm_or_si128(_mm_cmpgt_epi32(rectPacked, _mm_setzero_si128()),
+                              _mm_set_epi32(0, 0, 0xFFFFFFFF, 0xFFFFFFFF));
+  // Mask will now contain [ 0xFFFFFFFF 0xFFFFFFFF (width <= 0 ? 0 : 0xFFFFFFFF)
+  // (height <= 0 ? 0 : 0xFFFFFFFF) ]
+  rectPacked = _mm_and_si128(rectPacked, mask);
+
+  _mm_storeu_si128((__m128i*)&rect, rectPacked);
+#else
+  rect.SetNonEmptyBox(
+      NSToIntRoundUp(NSAppUnitsToFloatPixels(x, aAppUnitsPerPixel) * aXScale),
+      NSToIntRoundUp(NSAppUnitsToFloatPixels(y, aAppUnitsPerPixel) * aYScale),
+      NSToIntRoundUp(NSAppUnitsToFloatPixels(XMost(), aAppUnitsPerPixel) *
+                     aXScale),
+      NSToIntRoundUp(NSAppUnitsToFloatPixels(YMost(), aAppUnitsPerPixel) *
+                     aYScale));
+#endif
+  return rect;
+}
+
+// scale the rect but round to smallest containing rect
+inline mozilla::gfx::IntRect nsRect::ScaleToOutsidePixels(
+    float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const {
+  mozilla::gfx::IntRect rect;
+  // Android x86 builds have bindgen issues.
+#if !defined(ANDROID) && (defined(__SSE2__) || defined(_M_X64) || \
+                          (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
+  __m128 appUnitsPacked = _mm_set_ps(aAppUnitsPerPixel, aAppUnitsPerPixel,
+                                     aAppUnitsPerPixel, aAppUnitsPerPixel);
+  __m128 scalesPacked = _mm_set_ps(aYScale, aXScale, aYScale, aXScale);
+
+  __m128i rectPacked = _mm_loadu_si128((__m128i*)this);  // x, y, w, h
+  __m128i topLeft = _mm_slli_si128(rectPacked, 8);       // 0, 0, x, y
+
+  rectPacked = _mm_add_epi32(rectPacked, topLeft);  // X, Y, XMost(), YMost()
+
+  __m128 rectFloat = _mm_cvtepi32_ps(rectPacked);
+
+  // Scale i.e. ([ x y xmost ymost ] / aAppUnitsPerPixel) *
+  //             [ aXScale aYScale aXScale aYScale ]
+  rectFloat = _mm_mul_ps(_mm_div_ps(rectFloat, appUnitsPacked), scalesPacked);
+  rectPacked = ceil_ps2epi32(rectFloat);    // xx, xx, XMost(), YMost()
+  __m128i tmp = floor_ps2epi32(rectFloat);  // x, y, xx, xx
+
+  // _mm_move_sd is 1 cycle method of getting the blending we want.
+  rectPacked = _mm_castpd_si128(
+      _mm_move_sd(_mm_castsi128_pd(rectPacked),
+                  _mm_castsi128_pd(tmp)));  // x, y, XMost(), YMost()
+
+  topLeft = _mm_slli_si128(rectPacked, 8);          // 0, 0, r.x, r.y
+  rectPacked = _mm_sub_epi32(rectPacked, topLeft);  // r.x, r.y, r.w, r.h
+
+  // Avoid negative width/height due to overflow.
+  __m128i mask = _mm_or_si128(_mm_cmpgt_epi32(rectPacked, _mm_setzero_si128()),
+                              _mm_set_epi32(0, 0, 0xFFFFFFFF, 0xFFFFFFFF));
+  // clang-format off
+  // Mask will now contain [ 0xFFFFFFFF 0xFFFFFFFF (width <= 0 ? 0 : 0xFFFFFFFF) (height <= 0 ? 0 : 0xFFFFFFFF) ]
+  // clang-format on
+  rectPacked = _mm_and_si128(rectPacked, mask);
+
+  _mm_storeu_si128((__m128i*)&rect, rectPacked);
+#else
+  rect.SetNonEmptyBox(
+      NSToIntFloor(NSAppUnitsToFloatPixels(x, float(aAppUnitsPerPixel)) *
+                   aXScale),
+      NSToIntFloor(NSAppUnitsToFloatPixels(y, float(aAppUnitsPerPixel)) *
+                   aYScale),
+      NSToIntCeil(NSAppUnitsToFloatPixels(XMost(), float(aAppUnitsPerPixel)) *
+                  aXScale),
+      NSToIntCeil(NSAppUnitsToFloatPixels(YMost(), float(aAppUnitsPerPixel)) *
+                  aYScale));
+#endif
+  return rect;
+}
+
+// scale the rect but round to largest contained rect
+inline mozilla::gfx::IntRect nsRect::ScaleToInsidePixels(
+    float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const {
+  mozilla::gfx::IntRect rect;
+  rect.SetNonEmptyBox(
+      NSToIntCeil(NSAppUnitsToFloatPixels(x, float(aAppUnitsPerPixel)) *
+                  aXScale),
+      NSToIntCeil(NSAppUnitsToFloatPixels(y, float(aAppUnitsPerPixel)) *
+                  aYScale),
+      NSToIntFloor(NSAppUnitsToFloatPixels(XMost(), float(aAppUnitsPerPixel)) *
+                   aXScale),
+      NSToIntFloor(NSAppUnitsToFloatPixels(YMost(), float(aAppUnitsPerPixel)) *
+                   aYScale));
+  return rect;
+}
+
+inline mozilla::gfx::IntRect nsRect::ToNearestPixels(
+    nscoord aAppUnitsPerPixel) const {
+  return ScaleToNearestPixels(1.0f, 1.0f, aAppUnitsPerPixel);
+}
+
+inline mozilla::gfx::IntRect nsRect::ToOutsidePixels(
+    nscoord aAppUnitsPerPixel) const {
+  return ScaleToOutsidePixels(1.0f, 1.0f, aAppUnitsPerPixel);
+}
+
+inline mozilla::gfx::IntRect nsRect::ToInsidePixels(
+    nscoord aAppUnitsPerPixel) const {
+  return ScaleToInsidePixels(1.0f, 1.0f, aAppUnitsPerPixel);
+}
+
+inline nsRect nsRect::RemoveResolution(const float aResolution) const {
+  MOZ_ASSERT(aResolution > 0.0f);
+  nsRect rect;
+  rect.MoveTo(NSToCoordRound(NSCoordToFloat(x) / aResolution),
+              NSToCoordRound(NSCoordToFloat(y) / aResolution));
+  // A 1x1 rect indicates we are just hit testing a point, so pass down a 1x1
+  // rect as well instead of possibly rounding the width or height to zero.
+  if (width == 1 && height == 1) {
+    rect.SizeTo(1, 1);
+  } else {
+    rect.SizeTo(NSToCoordCeil(NSCoordToFloat(width) / aResolution),
+                NSToCoordCeil(NSCoordToFloat(height) / aResolution));
+  }
+
+  return rect;
+}
+
+const mozilla::gfx::IntRect& GetMaxSizedIntRect();
+
+// app units are integer multiples of pixels, so no rounding needed
+template <class units>
+nsRect ToAppUnits(const mozilla::gfx::IntRectTyped<units>& aRect,
+                  nscoord aAppUnitsPerPixel) {
+  return nsRect(NSIntPixelsToAppUnits(aRect.X(), aAppUnitsPerPixel),
+                NSIntPixelsToAppUnits(aRect.Y(), aAppUnitsPerPixel),
+                NSIntPixelsToAppUnits(aRect.Width(), aAppUnitsPerPixel),
+                NSIntPixelsToAppUnits(aRect.Height(), aAppUnitsPerPixel));
+}
+
+#endif /* NSRECT_H */
diff --git a/gfx/src/nsRectAbsolute.h b/gfx/src/nsRectAbsolute.h
new file mode 100644
index 0000000000..2ebedbffd7
--- /dev/null
+++ b/gfx/src/nsRectAbsolute.h
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSRECTABSOLUTE_H
+#define NSRECTABSOLUTE_H
+
+#include "mozilla/gfx/RectAbsolute.h"
+#include "nsCoord.h"
+#include "nsMargin.h"
+#include "nsRect.h"
+
+struct nsRectAbsolute
+    : public mozilla::gfx::BaseRectAbsolute<nscoord, nsRectAbsolute, nsPoint,
+                                            nsRect> {
+  typedef mozilla::gfx::BaseRectAbsolute<nscoord, nsRectAbsolute, nsPoint,
+                                         nsRect>
+      Super;
+
+  nsRectAbsolute() : Super() {}
+  nsRectAbsolute(nscoord aX1, nscoord aY1, nscoord aX2, nscoord aY2)
+      : Super(aX1, aY1, aX2, aY2) {}
+
+  MOZ_ALWAYS_INLINE nscoord SafeWidth() const {
+    int64_t width = right;
+    width -= left;
+    return nscoord(
+        std::min<int64_t>(std::numeric_limits<nscoord>::max(), width));
+  }
+  MOZ_ALWAYS_INLINE nscoord SafeHeight() const {
+    int64_t height = bottom;
+    height -= top;
+    return nscoord(
+        std::min<int64_t>(std::numeric_limits<nscoord>::max(), height));
+  }
+
+  nsRect ToNSRect() const {
+    return nsRect(left, top, nscoord(SafeWidth()), nscoord(SafeHeight()));
+  }
+
+  [[nodiscard]] nsRectAbsolute UnsafeUnion(const nsRectAbsolute& aRect) const {
+    return Super::Union(aRect);
+  }
+
+  void Inflate(const nsMargin& aMargin) {
+    left -= aMargin.left;
+    top -= aMargin.top;
+    right += aMargin.right;
+    bottom += aMargin.bottom;
+  }
+};
+
+#endif /* NSRECTABSOLUTE_H */
diff --git a/gfx/src/nsRegion.cpp b/gfx/src/nsRegion.cpp
new file mode 100644
index 0000000000..aa50d44fc4
--- /dev/null
+++ b/gfx/src/nsRegion.cpp
@@ -0,0 +1,1024 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsRegion.h"
+#include "nsTArray.h"
+#include "gfxUtils.h"
+#include "gfx2DGlue.h"
+#include "mozilla/ToString.h"
+
+void nsRegion::AssertStateInternal() const {
+  bool failed = false;
+  // Verify consistent state inside the region.
+  int32_t lastY = INT32_MIN;
+  int32_t lowestX = INT32_MAX;
+  int32_t highestX = INT32_MIN;
+  for (auto iter = mBands.begin(); iter != mBands.end(); iter++) {
+    const Band& band = *iter;
+    if (band.bottom <= band.top) {
+      failed = true;
+      break;
+    }
+    if (band.top < lastY) {
+      failed = true;
+      break;
+    }
+    lastY = band.bottom;
+
+    lowestX = std::min(lowestX, band.mStrips.begin()->left);
+    highestX = std::max(highestX, band.mStrips.LastElement().right);
+
+    int32_t lastX = INT32_MIN;
+    if (iter != mBands.begin()) {
+      auto prev = iter;
+      prev--;
+
+      if (prev->bottom == iter->top) {
+        if (band.EqualStrips(*prev)) {
+          failed = true;
+          break;
+        }
+      }
+    }
+    for (const Strip& strip : band.mStrips) {
+      if (strip.right <= strip.left) {
+        failed = true;
+        break;
+      }
+      if (strip.left <= lastX) {
+        failed = true;
+        break;
+      }
+      lastX = strip.right;
+    }
+    if (failed) {
+      break;
+    }
+  }
+
+  if (!(mBounds.IsEqualEdges(CalculateBounds()))) {
+    failed = true;
+  }
+
+  if (failed) {
+#ifdef DEBUG_REGIONS
+    if (mCurrentOpGenerator) {
+      mCurrentOpGenerator->OutputOp();
+    }
+#endif
+    MOZ_ASSERT(false);
+  }
+}
+
+bool nsRegion::Contains(const nsRegion& aRgn) const {
+  // XXX this could be made faster by iterating over
+  // both regions at the same time some how
+  for (auto iter = aRgn.RectIter(); !iter.Done(); iter.Next()) {
+    if (!Contains(iter.Get())) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool nsRegion::Intersects(const nsRectAbsolute& aRect) const {
+  if (mBands.IsEmpty()) {
+    return mBounds.Intersects(aRect);
+  }
+
+  if (!mBounds.Intersects(aRect)) {
+    return false;
+  }
+
+  Strip rectStrip(aRect.X(), aRect.XMost());
+
+  auto iter = mBands.begin();
+  while (iter != mBands.end()) {
+    if (iter->top >= aRect.YMost()) {
+      return false;
+    }
+
+    if (iter->bottom <= aRect.Y()) {
+      // This band is entirely before aRect, move on.
+      iter++;
+      continue;
+    }
+
+    if (!iter->Intersects(rectStrip)) {
+      // This band does not intersect aRect horizontally. Move on.
+      iter++;
+      continue;
+    }
+
+    // This band intersects with aRect.
+    return true;
+  }
+
+  return false;
+}
+
+void nsRegion::Inflate(const nsMargin& aMargin) {
+  nsRegion newRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    nsRectAbsolute rect = iter.GetAbsolute();
+    rect.Inflate(aMargin);
+    newRegion.AddRect(rect);
+  }
+
+  *this = std::move(newRegion);
+}
+
+void nsRegion::SimplifyOutward(uint32_t aMaxRects) {
+  MOZ_ASSERT(aMaxRects >= 1, "Invalid max rect count");
+
+  if (GetNumRects() <= aMaxRects) {
+    return;
+  }
+
+  // Try combining rects in horizontal bands into a single rect
+  // The goal here is to try to keep groups of rectangles that are vertically
+  // discontiguous as separate rectangles in the final region. This is
+  // simple and fast to implement and page contents tend to vary more
+  // vertically than horizontally (which is why our rectangles are stored
+  // sorted by y-coordinate, too).
+  //
+  // Note: if boxes share y1 because of the canonical representation they
+  // will share y2
+
+  size_t idx = 0;
+
+  while (idx < mBands.Length()) {
+    size_t oldIdx = idx;
+    mBands[idx].mStrips.begin()->right =
+        mBands[idx].mStrips.LastElement().right;
+    mBands[idx].mStrips.TruncateLength(1);
+    idx++;
+
+    // Merge any bands with the same bounds.
+    while (idx < mBands.Length() &&
+           mBands[idx].mStrips.begin()->left ==
+               mBands[oldIdx].mStrips.begin()->left &&
+           mBands[idx].mStrips.LastElement().right ==
+               mBands[oldIdx].mStrips.begin()->right) {
+      mBands[oldIdx].bottom = mBands[idx].bottom;
+      mBands.RemoveElementAt(idx);
+    }
+  }
+
+  AssertState();
+
+  // mBands.size() is now equal to our rect count.
+  if (mBands.Length() > aMaxRects) {
+    *this = GetBounds();
+  }
+}
+
+// compute the covered area difference between two rows.
+// by iterating over both rows simultaneously and adding up
+// the additional increase in area caused by extending each
+// of the rectangles to the combined height of both rows
+uint32_t nsRegion::ComputeMergedAreaIncrease(const Band& aTopBand,
+                                             const Band& aBottomBand) {
+  uint32_t totalArea = 0;
+
+  uint32_t topHeight = aBottomBand.top - aTopBand.top;
+  uint32_t bottomHeight = aBottomBand.bottom - aTopBand.bottom;
+  uint32_t currentStripBottom = 0;
+
+  // This could be done with slightly better worse case performance by merging
+  // these two for-loops, but this makes the code a lot easier to understand.
+  for (auto& strip : aTopBand.mStrips) {
+    if (currentStripBottom == aBottomBand.mStrips.Length() ||
+        strip.right < aBottomBand.mStrips[currentStripBottom].left) {
+      totalArea += bottomHeight * strip.Size();
+      continue;
+    }
+
+    int32_t currentX = strip.left;
+    while (currentStripBottom != aBottomBand.mStrips.Length() &&
+           aBottomBand.mStrips[currentStripBottom].left < strip.right) {
+      if (currentX >= strip.right) {
+        break;
+      }
+      if (currentX < aBottomBand.mStrips[currentStripBottom].left) {
+        // Add the part that's not intersecting.
+        totalArea += (aBottomBand.mStrips[currentStripBottom].left - currentX) *
+                     bottomHeight;
+      }
+
+      currentX =
+          std::max(aBottomBand.mStrips[currentStripBottom].right, currentX);
+      currentStripBottom++;
+    }
+
+    // Add remainder of this strip.
+    if (currentX < strip.right) {
+      totalArea += (strip.right - currentX) * bottomHeight;
+    }
+    if (currentStripBottom) {
+      currentStripBottom--;
+    }
+  }
+  uint32_t currentStripTop = 0;
+  for (auto& strip : aBottomBand.mStrips) {
+    if (currentStripTop == aTopBand.mStrips.Length() ||
+        strip.right < aTopBand.mStrips[currentStripTop].left) {
+      totalArea += topHeight * strip.Size();
+      continue;
+    }
+
+    int32_t currentX = strip.left;
+    while (currentStripTop != aTopBand.mStrips.Length() &&
+           aTopBand.mStrips[currentStripTop].left < strip.right) {
+      if (currentX >= strip.right) {
+        break;
+      }
+      if (currentX < aTopBand.mStrips[currentStripTop].left) {
+        // Add the part that's not intersecting.
+        totalArea +=
+            (aTopBand.mStrips[currentStripTop].left - currentX) * topHeight;
+      }
+
+      currentX = std::max(aTopBand.mStrips[currentStripTop].right, currentX);
+      currentStripTop++;
+    }
+
+    // Add remainder of this strip.
+    if (currentX < strip.right) {
+      totalArea += (strip.right - currentX) * topHeight;
+    }
+    if (currentStripTop) {
+      currentStripTop--;
+    }
+  }
+  return totalArea;
+}
+
+void nsRegion::SimplifyOutwardByArea(uint32_t aThreshold) {
+  if (mBands.Length() < 2) {
+    // We have only one or no row and we're done.
+    return;
+  }
+
+  uint32_t currentBand = 0;
+  do {
+    Band& band = mBands[currentBand];
+
+    uint32_t totalArea =
+        ComputeMergedAreaIncrease(band, mBands[currentBand + 1]);
+
+    if (totalArea <= aThreshold) {
+      for (Strip& strip : mBands[currentBand + 1].mStrips) {
+        // This could use an optimized function to merge two bands.
+        band.InsertStrip(strip);
+      }
+      band.bottom = mBands[currentBand + 1].bottom;
+      mBands.RemoveElementAt(currentBand + 1);
+    } else {
+      currentBand++;
+    }
+  } while (currentBand + 1 < mBands.Length());
+
+  EnsureSimplified();
+  AssertState();
+}
+
+typedef void (*visit_fn)(void* closure, VisitSide side, int x1, int y1, int x2,
+                         int y2);
+
+void nsRegion::VisitEdges(visit_fn visit, void* closure) const {
+  if (mBands.IsEmpty()) {
+    visit(closure, VisitSide::LEFT, mBounds.X(), mBounds.Y(), mBounds.X(),
+          mBounds.YMost());
+    visit(closure, VisitSide::RIGHT, mBounds.XMost(), mBounds.Y(),
+          mBounds.XMost(), mBounds.YMost());
+    visit(closure, VisitSide::TOP, mBounds.X() - 1, mBounds.Y(),
+          mBounds.XMost() + 1, mBounds.Y());
+    visit(closure, VisitSide::BOTTOM, mBounds.X() - 1, mBounds.YMost(),
+          mBounds.XMost() + 1, mBounds.YMost());
+    return;
+  }
+
+  auto band = std::begin(mBands);
+  auto bandFinal = std::end(mBands);
+  bandFinal--;
+  for (const Strip& strip : band->mStrips) {
+    visit(closure, VisitSide::LEFT, strip.left, band->top, strip.left,
+          band->bottom);
+    visit(closure, VisitSide::RIGHT, strip.right, band->top, strip.right,
+          band->bottom);
+    visit(closure, VisitSide::TOP, strip.left - 1, band->top, strip.right + 1,
+          band->top);
+  }
+
+  if (band != bandFinal) {
+    do {
+      const Band& topBand = *band;
+      band++;
+
+      for (const Strip& strip : band->mStrips) {
+        visit(closure, VisitSide::LEFT, strip.left, band->top, strip.left,
+              band->bottom);
+        visit(closure, VisitSide::RIGHT, strip.right, band->top, strip.right,
+              band->bottom);
+      }
+
+      if (band->top == topBand.bottom) {
+        // Two bands touching each other vertically.
+        const Band& bottomBand = *band;
+        auto topStrip = std::begin(topBand.mStrips);
+        auto bottomStrip = std::begin(bottomBand.mStrips);
+
+        int y = topBand.bottom;
+
+        // State from this point on along the vertical edge:
+        // 0 - Empty
+        // 1 - Touched by top rect
+        // 2 - Touched by bottom rect
+        // 3 - Touched on both sides
+        int state;
+        const int TouchedByNothing = 0;
+        const int TouchedByTop = 1;
+        const int TouchedByBottom = 2;
+        // We always start with nothing.
+        int oldState = TouchedByNothing;
+        // Last state change, adjusted by -1 if the last state change was
+        // a change away from 0.
+        int lastX = std::min(topStrip->left, bottomStrip->left) - 1;
+
+        // Current edge being considered for top and bottom,
+        // 0 - left, 1 - right.
+        bool topEdgeIsLeft = true;
+        bool bottomEdgeIsLeft = true;
+        while (topStrip != std::end(topBand.mStrips) &&
+               bottomStrip != std::end(bottomBand.mStrips)) {
+          int topPos;
+          int bottomPos;
+          if (topEdgeIsLeft) {
+            topPos = topStrip->left;
+          } else {
+            topPos = topStrip->right;
+          }
+          if (bottomEdgeIsLeft) {
+            bottomPos = bottomStrip->left;
+          } else {
+            bottomPos = bottomStrip->right;
+          }
+
+          int currentX = std::min(topPos, bottomPos);
+          if (topPos < bottomPos) {
+            if (topEdgeIsLeft) {
+              state = oldState | TouchedByTop;
+            } else {
+              state = oldState ^ TouchedByTop;
+              topStrip++;
+            }
+            topEdgeIsLeft = !topEdgeIsLeft;
+          } else if (bottomPos < topPos) {
+            if (bottomEdgeIsLeft) {
+              state = oldState | TouchedByBottom;
+            } else {
+              state = oldState ^ TouchedByBottom;
+              bottomStrip++;
+            }
+            bottomEdgeIsLeft = !bottomEdgeIsLeft;
+          } else {
+            // bottomPos == topPos
+            state = TouchedByNothing;
+            if (bottomEdgeIsLeft) {
+              state = TouchedByBottom;
+            } else {
+              bottomStrip++;
+            }
+            if (topEdgeIsLeft) {
+              state |= TouchedByTop;
+            } else {
+              topStrip++;
+            }
+            topEdgeIsLeft = !topEdgeIsLeft;
+            bottomEdgeIsLeft = !bottomEdgeIsLeft;
+          }
+
+          MOZ_ASSERT(state != oldState);
+          if (oldState == TouchedByNothing) {
+            // We had nothing before, make sure the left edge will be padded.
+            lastX = currentX - 1;
+          } else if (oldState == TouchedByTop) {
+            if (state == TouchedByNothing) {
+              visit(closure, VisitSide::BOTTOM, lastX, y, currentX + 1, y);
+            } else {
+              visit(closure, VisitSide::BOTTOM, lastX, y, currentX, y);
+              lastX = currentX;
+            }
+          } else if (oldState == TouchedByBottom) {
+            if (state == TouchedByNothing) {
+              visit(closure, VisitSide::TOP, lastX, y, currentX + 1, y);
+            } else {
+              visit(closure, VisitSide::TOP, lastX, y, currentX, y);
+              lastX = currentX;
+            }
+          } else {
+            lastX = currentX;
+          }
+          oldState = state;
+        }
+
+        MOZ_ASSERT(!state || (topEdgeIsLeft || bottomEdgeIsLeft));
+        if (topStrip != std::end(topBand.mStrips)) {
+          if (!topEdgeIsLeft) {
+            visit(closure, VisitSide::BOTTOM, lastX, y, topStrip->right + 1, y);
+            topStrip++;
+          }
+          while (topStrip != std::end(topBand.mStrips)) {
+            visit(closure, VisitSide::BOTTOM, topStrip->left - 1, y,
+                  topStrip->right + 1, y);
+            topStrip++;
+          }
+        } else if (bottomStrip != std::end(bottomBand.mStrips)) {
+          if (!bottomEdgeIsLeft) {
+            visit(closure, VisitSide::TOP, lastX, y, bottomStrip->right + 1, y);
+            bottomStrip++;
+          }
+          while (bottomStrip != std::end(bottomBand.mStrips)) {
+            visit(closure, VisitSide::TOP, bottomStrip->left - 1, y,
+                  bottomStrip->right + 1, y);
+            bottomStrip++;
+          }
+        }
+      } else {
+        for (const Strip& strip : topBand.mStrips) {
+          visit(closure, VisitSide::BOTTOM, strip.left - 1, topBand.bottom,
+                strip.right + 1, topBand.bottom);
+        }
+        for (const Strip& strip : band->mStrips) {
+          visit(closure, VisitSide::TOP, strip.left - 1, band->top,
+                strip.right + 1, band->top);
+        }
+      }
+    } while (band != bandFinal);
+  }
+
+  for (const Strip& strip : band->mStrips) {
+    visit(closure, VisitSide::BOTTOM, strip.left - 1, band->bottom,
+          strip.right + 1, band->bottom);
+  }
+}
+
+void nsRegion::SimplifyInward(uint32_t aMaxRects) {
+  NS_ASSERTION(aMaxRects >= 1, "Invalid max rect count");
+
+  if (GetNumRects() <= aMaxRects) return;
+
+  SetEmpty();
+}
+
+uint64_t nsRegion::Area() const {
+  if (mBands.IsEmpty()) {
+    return mBounds.Area();
+  }
+
+  uint64_t area = 0;
+  for (const Band& band : mBands) {
+    uint32_t height = band.bottom - band.top;
+    for (const Strip& strip : band.mStrips) {
+      area += (strip.right - strip.left) * height;
+    }
+  }
+
+  return area;
+}
+
+nsRegion& nsRegion::ScaleRoundOut(float aXScale, float aYScale) {
+  if (mozilla::gfx::FuzzyEqual(aXScale, 1.0f) &&
+      mozilla::gfx::FuzzyEqual(aYScale, 1.0f)) {
+    return *this;
+  }
+
+  nsRegion newRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    nsRectAbsolute rect = iter.GetAbsolute();
+    rect.ScaleRoundOut(aXScale, aYScale);
+    newRegion.AddRect(rect);
+  }
+
+  *this = std::move(newRegion);
+  return *this;
+}
+
+nsRegion& nsRegion::ScaleInverseRoundOut(float aXScale, float aYScale) {
+  nsRegion newRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    nsRectAbsolute rect = iter.GetAbsolute();
+    rect.ScaleInverseRoundOut(aXScale, aYScale);
+    newRegion.AddRect(rect);
+  }
+
+  *this = std::move(newRegion);
+  return *this;
+}
+
+static mozilla::gfx::IntRect TransformRect(
+    const mozilla::gfx::IntRect& aRect,
+    const mozilla::gfx::Matrix4x4& aTransform) {
+  if (aRect.IsEmpty()) {
+    return mozilla::gfx::IntRect();
+  }
+
+  mozilla::gfx::RectDouble rect(aRect.X(), aRect.Y(), aRect.Width(),
+                                aRect.Height());
+  rect = aTransform.TransformAndClipBounds(
+      rect, mozilla::gfx::RectDouble::MaxIntRect());
+  rect.RoundOut();
+
+  mozilla::gfx::IntRect intRect;
+  if (!gfxUtils::GfxRectToIntRect(ThebesRect(rect), &intRect)) {
+    return mozilla::gfx::IntRect();
+  }
+
+  return intRect;
+}
+
+nsRegion& nsRegion::Transform(const mozilla::gfx::Matrix4x4& aTransform) {
+  nsRegion newRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    nsRect rect = nsIntRegion::ToRect(
+        TransformRect(nsIntRegion::FromRect(iter.Get()), aTransform));
+    newRegion.AddRect(nsRectAbsolute::FromRect(rect));
+  }
+
+  *this = std::move(newRegion);
+  return *this;
+}
+
+nsRegion nsRegion::ScaleToOtherAppUnitsRoundOut(int32_t aFromAPP,
+                                                int32_t aToAPP) const {
+  if (aFromAPP == aToAPP) {
+    return *this;
+  }
+  nsRegion newRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    nsRect rect = iter.Get();
+    rect = rect.ScaleToOtherAppUnitsRoundOut(aFromAPP, aToAPP);
+    newRegion.AddRect(nsRectAbsolute::FromRect(rect));
+  }
+
+  return newRegion;
+}
+
+nsRegion nsRegion::ScaleToOtherAppUnitsRoundIn(int32_t aFromAPP,
+                                               int32_t aToAPP) const {
+  if (aFromAPP == aToAPP) {
+    return *this;
+  }
+
+  nsRegion newRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    nsRect rect = iter.Get();
+    rect = rect.ScaleToOtherAppUnitsRoundIn(aFromAPP, aToAPP);
+    newRegion.AddRect(nsRectAbsolute::FromRect(rect));
+  }
+
+  return newRegion;
+}
+
+nsIntRegion nsRegion::ToPixels(nscoord aAppUnitsPerPixel,
+                               bool aOutsidePixels) const {
+  nsIntRegion intRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    mozilla::gfx::IntRect deviceRect;
+    nsRect rect = iter.Get();
+    if (aOutsidePixels)
+      deviceRect = rect.ToOutsidePixels(aAppUnitsPerPixel);
+    else
+      deviceRect = rect.ToNearestPixels(aAppUnitsPerPixel);
+    intRegion.OrWith(deviceRect);
+  }
+
+  return intRegion;
+}
+
+nsIntRegion nsRegion::ToOutsidePixels(nscoord aAppUnitsPerPixel) const {
+  return ToPixels(aAppUnitsPerPixel, true);
+}
+
+nsIntRegion nsRegion::ToNearestPixels(nscoord aAppUnitsPerPixel) const {
+  return ToPixels(aAppUnitsPerPixel, false);
+}
+
+nsIntRegion nsRegion::ScaleToNearestPixels(float aScaleX, float aScaleY,
+                                           nscoord aAppUnitsPerPixel) const {
+  nsIntRegion result;
+  for (auto iter = RectIter(); !iter.Done(); iter.Next()) {
+    mozilla::gfx::IntRect deviceRect =
+        iter.Get().ScaleToNearestPixels(aScaleX, aScaleY, aAppUnitsPerPixel);
+    result.Or(result, deviceRect);
+  }
+  return result;
+}
+
+nsIntRegion nsRegion::ScaleToOutsidePixels(float aScaleX, float aScaleY,
+                                           nscoord aAppUnitsPerPixel) const {
+  // make a copy of the region so that we can mutate it inplace
+  nsIntRegion intRegion;
+  for (RectIterator iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+    nsRect rect = iter.Get();
+    intRegion.OrWith(
+        rect.ScaleToOutsidePixels(aScaleX, aScaleY, aAppUnitsPerPixel));
+  }
+  return intRegion;
+}
+
+nsIntRegion nsRegion::ScaleToInsidePixels(float aScaleX, float aScaleY,
+                                          nscoord aAppUnitsPerPixel) const {
+  /* When scaling a rect, walk forward through the rect list up until the y
+   * value is greater than the current rect's YMost() value.
+   *
+   * For each rect found, check if the rects have a touching edge (in unscaled
+   * coordinates), and if one edge is entirely contained within the other.
+   *
+   * If it is, then the contained edge can be moved (in scaled pixels) to ensure
+   * that no gap exists.
+   *
+   * Since this could be potentially expensive - O(n^2), we only attempt this
+   * algorithm for the first rect.
+   */
+
+  if (mBands.IsEmpty()) {
+    nsIntRect rect = mBounds.ToNSRect().ScaleToInsidePixels(aScaleX, aScaleY,
+                                                            aAppUnitsPerPixel);
+    return nsIntRegion(rect);
+  }
+
+  nsIntRegion intRegion;
+  RectIterator iter = RectIterator(*this);
+
+  nsRect first = iter.Get();
+
+  mozilla::gfx::IntRect firstDeviceRect =
+      first.ScaleToInsidePixels(aScaleX, aScaleY, aAppUnitsPerPixel);
+
+  for (iter.Next(); !iter.Done(); iter.Next()) {
+    nsRect rect = iter.Get();
+    mozilla::gfx::IntRect deviceRect =
+        rect.ScaleToInsidePixels(aScaleX, aScaleY, aAppUnitsPerPixel);
+
+    if (rect.Y() <= first.YMost()) {
+      if (rect.XMost() == first.X() && rect.YMost() <= first.YMost()) {
+        // rect is touching on the left edge of the first rect and contained
+        // within the length of its left edge
+        deviceRect.SetRightEdge(firstDeviceRect.X());
+      } else if (rect.X() == first.XMost() && rect.YMost() <= first.YMost()) {
+        // rect is touching on the right edge of the first rect and contained
+        // within the length of its right edge
+        deviceRect.SetLeftEdge(firstDeviceRect.XMost());
+      } else if (rect.Y() == first.YMost()) {
+        // The bottom of the first rect is on the same line as the top of rect,
+        // but they aren't necessarily contained.
+        if (rect.X() <= first.X() && rect.XMost() >= first.XMost()) {
+          // The top of rect contains the bottom of the first rect
+          firstDeviceRect.SetBottomEdge(deviceRect.Y());
+        } else if (rect.X() >= first.X() && rect.XMost() <= first.XMost()) {
+          // The bottom of the first contains the top of rect
+          deviceRect.SetTopEdge(firstDeviceRect.YMost());
+        }
+      }
+    }
+
+    intRegion.OrWith(deviceRect);
+  }
+
+  intRegion.OrWith(firstDeviceRect);
+  return intRegion;
+}
+
+// A cell's "value" is a pair consisting of
+// a) the area of the subrectangle it corresponds to, if it's in
+// aContainingRect and in the region, 0 otherwise
+// b) the area of the subrectangle it corresponds to, if it's in the region,
+// 0 otherwise
+// Addition, subtraction and identity are defined on these values in the
+// obvious way. Partial order is lexicographic.
+// A "large negative value" is defined with large negative numbers for both
+// fields of the pair. This negative value has the property that adding any
+// number of non-negative values to it always results in a negative value.
+//
+// The GetLargestRectangle algorithm works in three phases:
+//  1) Convert the region into a grid by adding vertical/horizontal lines for
+//     each edge of each rectangle in the region.
+//  2) For each rectangle in the region, for each cell it contains, set that
+//     cells's value as described above.
+//  3) Calculate the submatrix with the largest sum such that none of its cells
+//     contain any 0s (empty regions). The rectangle represented by the
+//     submatrix is the largest rectangle in the region.
+//
+// Let k be the number of rectangles in the region.
+// Let m be the height of the grid generated in step 1.
+// Let n be the width of the grid generated in step 1.
+//
+// Step 1 is O(k) in time and O(m+n) in space for the sparse grid.
+// Step 2 is O(mn) in time and O(mn) in additional space for the full grid.
+// Step 3 is O(m^2 n) in time and O(mn) in additional space
+//
+// The implementation of steps 1 and 2 are rather straightforward. However our
+// implementation of step 3 uses dynamic programming to achieve its efficiency.
+//
+// Psuedo code for step 3 is as follows where G is the grid from step 1 and A
+// is the array from step 2:
+// Phase3 = function (G, A, m, n) {
+//   let (t,b,l,r,_) = MaxSum2D(A,m,n)
+//   return rect(G[t],G[l],G[r],G[b]);
+// }
+// MaxSum2D = function (A, m, n) {
+//   S = array(m+1,n+1)
+//   S[0][i] = 0 for i in [0,n]
+//   S[j][0] = 0 for j in [0,m]
+//   S[j][i] = (if A[j-1][i-1] = 0 then some large negative value
+//                                 else A[j-1][i-1])
+//           + S[j-1][n] + S[j][i-1] - S[j-1][i-1]
+//
+//   // top, bottom, left, right, area
+//   var maxRect = (-1, -1, -1, -1, 0);
+//
+//   for all (m',m'') in [0, m]^2 {
+//     let B = { S[m'][i] - S[m''][i] | 0 <= i <= n }
+//     let ((l,r),area) = MaxSum1D(B,n+1)
+//     if (area > maxRect.area) {
+//       maxRect := (m', m'', l, r, area)
+//     }
+//   }
+//
+//   return maxRect;
+// }
+//
+// Originally taken from Improved algorithms for the k-maximum subarray problem
+// for small k - SE Bae, T Takaoka but modified to show the explicit tracking
+// of indices and we already have the prefix sums from our one call site so
+// there's no need to construct them.
+// MaxSum1D = function (A,n) {
+//   var minIdx = 0;
+//   var min = 0;
+//   var maxIndices = (0,0);
+//   var max = 0;
+//   for i in range(n) {
+//     let cand = A[i] - min;
+//     if (cand > max) {
+//       max := cand;
+//       maxIndices := (minIdx, i)
+//     }
+//     if (min > A[i]) {
+//       min := A[i];
+//       minIdx := i;
+//     }
+//   }
+//   return (minIdx, maxIdx, max);
+// }
+
+namespace {
+// This class represents a partitioning of an axis delineated by coordinates.
+// It internally maintains a sorted array of coordinates.
+class AxisPartition {
+ public:
+  // Adds a new partition at the given coordinate to this partitioning. If
+  // the coordinate is already present in the partitioning, this does nothing.
+  void InsertCoord(nscoord c) {
+    uint32_t i = mStops.IndexOfFirstElementGt(c);
+    if (i == 0 || mStops[i - 1] != c) {
+      mStops.InsertElementAt(i, c);
+    }
+  }
+
+  // Returns the array index of the given partition point. The partition
+  // point must already be present in the partitioning.
+  int32_t IndexOf(nscoord p) const { return mStops.BinaryIndexOf(p); }
+
+  // Returns the partition at the given index which must be non-zero and
+  // less than the number of partitions in this partitioning.
+  nscoord StopAt(int32_t index) const { return mStops[index]; }
+
+  // Returns the size of the gap between the partition at the given index and
+  // the next partition in this partitioning. If the index is the last index
+  // in the partitioning, the result is undefined.
+  nscoord StopSize(int32_t index) const {
+    return mStops[index + 1] - mStops[index];
+  }
+
+  // Returns the number of partitions in this partitioning.
+  int32_t GetNumStops() const { return mStops.Length(); }
+
+ private:
+  nsTArray<nscoord> mStops;
+};
+
+const int64_t kVeryLargeNegativeNumber = 0xffff000000000000ll;
+
+struct SizePair {
+  int64_t mSizeContainingRect;
+  int64_t mSize;
+
+  SizePair() : mSizeContainingRect(0), mSize(0) {}
+
+  static SizePair VeryLargeNegative() {
+    SizePair result;
+    result.mSize = result.mSizeContainingRect = kVeryLargeNegativeNumber;
+    return result;
+  }
+  bool operator<(const SizePair& aOther) const {
+    if (mSizeContainingRect < aOther.mSizeContainingRect) return true;
+    if (mSizeContainingRect > aOther.mSizeContainingRect) return false;
+    return mSize < aOther.mSize;
+  }
+  bool operator>(const SizePair& aOther) const {
+    return aOther.operator<(*this);
+  }
+  SizePair operator+(const SizePair& aOther) const {
+    SizePair result = *this;
+    result.mSizeContainingRect += aOther.mSizeContainingRect;
+    result.mSize += aOther.mSize;
+    return result;
+  }
+  SizePair operator-(const SizePair& aOther) const {
+    SizePair result = *this;
+    result.mSizeContainingRect -= aOther.mSizeContainingRect;
+    result.mSize -= aOther.mSize;
+    return result;
+  }
+};
+
+// Returns the sum and indices of the subarray with the maximum sum of the
+// given array (A,n), assuming the array is already in prefix sum form.
+SizePair MaxSum1D(const nsTArray<SizePair>& A, int32_t n, int32_t* minIdx,
+                  int32_t* maxIdx) {
+  // The min/max indicies of the largest subarray found so far
+  SizePair min, max;
+  int32_t currentMinIdx = 0;
+
+  *minIdx = 0;
+  *maxIdx = 0;
+
+  // Because we're given the array in prefix sum form, we know the first
+  // element is 0
+  for (int32_t i = 1; i < n; i++) {
+    SizePair cand = A[i] - min;
+    if (cand > max) {
+      max = cand;
+      *minIdx = currentMinIdx;
+      *maxIdx = i;
+    }
+    if (min > A[i]) {
+      min = A[i];
+      currentMinIdx = i;
+    }
+  }
+
+  return max;
+}
+}  // namespace
+
+nsRect nsRegion::GetLargestRectangle(const nsRect& aContainingRect) const {
+  nsRect bestRect;
+
+  if (GetNumRects() <= 1) {
+    bestRect = GetBounds();
+    return bestRect;
+  }
+
+  AxisPartition xaxis, yaxis;
+
+  // Step 1: Calculate the grid lines
+  for (auto iter = RectIter(); !iter.Done(); iter.Next()) {
+    const nsRect& rect = iter.Get();
+    xaxis.InsertCoord(rect.X());
+    xaxis.InsertCoord(rect.XMost());
+    yaxis.InsertCoord(rect.Y());
+    yaxis.InsertCoord(rect.YMost());
+  }
+  if (!aContainingRect.IsEmpty()) {
+    xaxis.InsertCoord(aContainingRect.X());
+    xaxis.InsertCoord(aContainingRect.XMost());
+    yaxis.InsertCoord(aContainingRect.Y());
+    yaxis.InsertCoord(aContainingRect.YMost());
+  }
+
+  // Step 2: Fill out the grid with the areas
+  // Note: due to the ordering of rectangles in the region, it is not always
+  // possible to combine steps 2 and 3 so we don't try to be clever.
+  int32_t matrixHeight = yaxis.GetNumStops() - 1;
+  int32_t matrixWidth = xaxis.GetNumStops() - 1;
+  int32_t matrixSize = matrixHeight * matrixWidth;
+  nsTArray<SizePair> areas(matrixSize);
+  areas.SetLength(matrixSize);
+
+  for (auto iter = RectIter(); !iter.Done(); iter.Next()) {
+    const nsRect& rect = iter.Get();
+    int32_t xstart = xaxis.IndexOf(rect.X());
+    int32_t xend = xaxis.IndexOf(rect.XMost());
+    int32_t y = yaxis.IndexOf(rect.Y());
+    int32_t yend = yaxis.IndexOf(rect.YMost());
+
+    for (; y < yend; y++) {
+      nscoord height = yaxis.StopSize(y);
+      for (int32_t x = xstart; x < xend; x++) {
+        nscoord width = xaxis.StopSize(x);
+        int64_t size = width * int64_t(height);
+        if (rect.Intersects(aContainingRect)) {
+          areas[y * matrixWidth + x].mSizeContainingRect = size;
+        }
+        areas[y * matrixWidth + x].mSize = size;
+      }
+    }
+  }
+
+  // Step 3: Find the maximum submatrix sum that does not contain a rectangle
+  {
+    // First get the prefix sum array
+    int32_t m = matrixHeight + 1;
+    int32_t n = matrixWidth + 1;
+    nsTArray<SizePair> pareas(m * n);
+    pareas.SetLength(m * n);
+    for (int32_t y = 1; y < m; y++) {
+      for (int32_t x = 1; x < n; x++) {
+        SizePair area = areas[(y - 1) * matrixWidth + x - 1];
+        if (!area.mSize) {
+          area = SizePair::VeryLargeNegative();
+        }
+        area = area + pareas[y * n + x - 1] + pareas[(y - 1) * n + x] -
+               pareas[(y - 1) * n + x - 1];
+        pareas[y * n + x] = area;
+      }
+    }
+
+    // No longer need the grid
+    areas.SetLength(0);
+
+    SizePair bestArea;
+    struct {
+      int32_t left, top, right, bottom;
+    } bestRectIndices = {0, 0, 0, 0};
+    for (int32_t m1 = 0; m1 < m; m1++) {
+      for (int32_t m2 = m1 + 1; m2 < m; m2++) {
+        nsTArray<SizePair> B;
+        B.SetLength(n);
+        for (int32_t i = 0; i < n; i++) {
+          B[i] = pareas[m2 * n + i] - pareas[m1 * n + i];
+        }
+        int32_t minIdx, maxIdx;
+        SizePair area = MaxSum1D(B, n, &minIdx, &maxIdx);
+        if (area > bestArea) {
+          bestRectIndices.left = minIdx;
+          bestRectIndices.top = m1;
+          bestRectIndices.right = maxIdx;
+          bestRectIndices.bottom = m2;
+          bestArea = area;
+        }
+      }
+    }
+
+    bestRect.MoveTo(xaxis.StopAt(bestRectIndices.left),
+                    yaxis.StopAt(bestRectIndices.top));
+    bestRect.SizeTo(xaxis.StopAt(bestRectIndices.right) - bestRect.X(),
+                    yaxis.StopAt(bestRectIndices.bottom) - bestRect.Y());
+  }
+
+  return bestRect;
+}
+
+std::ostream& operator<<(std::ostream& stream, const nsRegion& m) {
+  stream << "[";
+
+  bool first = true;
+  for (auto iter = m.RectIter(); !iter.Done(); iter.Next()) {
+    if (!first) {
+      stream << "; ";
+    } else {
+      first = false;
+    }
+    const nsRect& rect = iter.Get();
+    stream << rect.X() << "," << rect.Y() << "," << rect.XMost() << ","
+           << rect.YMost();
+  }
+
+  stream << "]";
+  return stream;
+}
+
+void nsRegion::OutputToStream(std::string aObjName,
+                              std::ostream& stream) const {
+  auto iter = RectIter();
+  nsRect r = iter.Get();
+  stream << "nsRegion " << aObjName << "(nsRect(" << r.X() << ", " << r.Y()
+         << ", " << r.Width() << ", " << r.Height() << "));\n";
+  iter.Next();
+
+  for (; !iter.Done(); iter.Next()) {
+    nsRect r = iter.Get();
+    stream << aObjName << ".OrWith(nsRect(" << r.X() << ", " << r.Y() << ", "
+           << r.Width() << ", " << r.Height() << "));\n";
+  }
+}
+
+nsCString nsRegion::ToString() const {
+  return nsCString(mozilla::ToString(*this).c_str());
+}
diff --git a/gfx/src/nsRegion.h b/gfx/src/nsRegion.h
new file mode 100644
index 0000000000..505e55e2f2
--- /dev/null
+++ b/gfx/src/nsRegion.h
@@ -0,0 +1,2532 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsRegion_h__
+#define nsRegion_h__
+
+#include <stddef.h>  // for size_t
+#include <stdint.h>  // for uint32_t, uint64_t
+
+#include <ostream>  // for std::ostream
+#include <utility>  // for mozilla::Move
+
+#include "mozilla/ArrayView.h"      // for ArrayView
+#include "mozilla/gfx/MatrixFwd.h"  // for mozilla::gfx::Matrix4x4
+#include "nsCoord.h"                // for nscoord
+#include "nsMargin.h"               // for nsIntMargin
+#include "nsPoint.h"                // for nsIntPoint, nsPoint
+#include "nsRect.h"                 // for mozilla::gfx::IntRect, nsRect
+#include "nsRectAbsolute.h"
+#include "nsRegionFwd.h"  // for nsIntRegion
+#include "nsString.h"     // for nsCString
+#include "nsTArray.h"
+#include "pixman.h"
+
+// Uncomment this line to get additional integrity checking.
+// #define DEBUG_REGIONS
+#ifdef DEBUG_REGIONS
+#  include <sstream>
+#endif
+
+/* For information on the internal representation look at pixman-region.c
+ *
+ * This replaces an older homebrew implementation of nsRegion. The
+ * representation used here may use more rectangles than nsRegion however, the
+ * representation is canonical.  This means that there's no need for an
+ * Optimize() method because for a paticular region there is only one
+ * representation. This means that nsIntRegion will have more predictable
+ * performance characteristics than the old nsRegion and should not become
+ * degenerate.
+ *
+ * The pixman region code originates from X11 which has spread to a variety of
+ * projects including Qt, Gtk, Wine. It should perform reasonably well.
+ */
+
+enum class VisitSide { TOP, BOTTOM, LEFT, RIGHT };
+
+namespace regiondetails {
+struct Band;
+}
+
+template <>
+struct nsTArray_RelocationStrategy<regiondetails::Band> {
+  typedef nsTArray_RelocateUsingMoveConstructor<regiondetails::Band> Type;
+};
+
+namespace regiondetails {
+
+template <typename T, typename E>
+class UncheckedArray : public T {
+ public:
+  using T::Elements;
+  using T::Length;
+
+  UncheckedArray() = default;
+  MOZ_IMPLICIT UncheckedArray(T&& aSrc) : T(std::move(aSrc)) {}
+
+  E& operator[](size_t aIndex) { return Elements()[aIndex]; }
+  const E& operator[](size_t aIndex) const { return Elements()[aIndex]; }
+  E& LastElement() { return Elements()[Length() - 1]; }
+  const E& LastElement() const { return Elements()[Length() - 1]; }
+
+  using iterator = E*;
+  using const_iterator = const E*;
+
+  iterator begin() { return iterator(Elements()); }
+  const_iterator begin() const { return const_iterator(Elements()); }
+  const_iterator cbegin() const { return begin(); }
+  iterator end() { return iterator(Elements() + Length()); }
+  const_iterator end() const { return const_iterator(Elements() + Length()); }
+  const_iterator cend() const { return end(); }
+};
+
+struct Strip {
+  // Default constructor should never be called, but is required for
+  // vector::resize to compile.
+  Strip() { MOZ_CRASH(); }
+  Strip(int32_t aLeft, int32_t aRight) : left(aLeft), right(aRight) {}
+
+  bool operator!=(const Strip& aOther) const {
+    return left != aOther.left || right != aOther.right;
+  }
+
+  uint32_t Size() const { return right - left; }
+
+  int32_t left;
+  int32_t right;
+};
+
+struct Band {
+  using Strip = regiondetails::Strip;
+#ifndef DEBUG
+  using StripArray =
+      regiondetails::UncheckedArray<CopyableAutoTArray<Strip, 2>, Strip>;
+#else
+  using StripArray = CopyableAutoTArray<Strip, 2>;
+#endif
+
+  MOZ_IMPLICIT Band(const nsRectAbsolute& aRect)
+      : top(aRect.Y()), bottom(aRect.YMost()) {
+    mStrips.AppendElement(Strip{aRect.X(), aRect.XMost()});
+  }
+
+  Band(const Band& aOther) = default;
+  Band(Band&& aOther) = default;
+
+  void InsertStrip(const Strip& aStrip) {
+    for (size_t i = 0; i < mStrips.Length(); i++) {
+      Strip& strip = mStrips[i];
+      if (strip.left > aStrip.right) {
+        // Current strip is beyond aStrip, insert aStrip before.
+        mStrips.InsertElementAt(i, aStrip);
+        return;
+      }
+
+      if (strip.right < aStrip.left) {
+        // Current strip is before aStrip, try the next.
+        continue;
+      }
+
+      // Current strip intersects with aStrip, extend to the lext.
+      strip.left = std::min(strip.left, aStrip.left);
+
+      if (strip.right >= aStrip.right) {
+        // Current strip extends beyond aStrip, done.
+        return;
+      }
+
+      size_t next = i;
+      next++;
+      // Consume any subsequent strips intersecting with aStrip.
+      while (next < mStrips.Length() && mStrips[next].left <= aStrip.right) {
+        strip.right = mStrips[next].right;
+
+        mStrips.RemoveElementAt(next);
+      }
+
+      // Extend the strip in case the aStrip goes on beyond it.
+      strip.right = std::max(strip.right, aStrip.right);
+      return;
+    }
+    mStrips.AppendElement(aStrip);
+  }
+
+  void SubStrip(const Strip& aStrip) {
+    for (size_t i = 0; i < mStrips.Length(); i++) {
+      Strip& strip = mStrips[i];
+      if (strip.left > aStrip.right) {
+        // Strip is entirely to the right of aStrip. Done.
+        return;
+      }
+
+      if (strip.right < aStrip.left) {
+        // Strip is entirely to the left of aStrip. Move on.
+        continue;
+      }
+
+      if (strip.left < aStrip.left) {
+        if (strip.right <= aStrip.right) {
+          strip.right = aStrip.left;
+          // This strip lies to the left of the start of aStrip.
+          continue;
+        }
+
+        // aStrip is completely contained by this strip.
+        Strip newStrip(aStrip.right, strip.right);
+        strip.right = aStrip.left;
+        if (i < mStrips.Length()) {
+          i++;
+          mStrips.InsertElementAt(i, newStrip);
+        } else {
+          mStrips.AppendElement(newStrip);
+        }
+        return;
+      }
+
+      // This strip lies to the right of the start of aStrip.
+      if (strip.right <= aStrip.right) {
+        // aStrip completely contains this strip.
+        mStrips.RemoveElementAt(i);
+        // Make sure we evaluate the strip now at i. This loop will increment.
+        i--;
+        continue;
+      }
+      strip.left = aStrip.right;
+      return;
+    }
+  }
+
+  bool Intersects(const Strip& aStrip) const {
+    for (const Strip& strip : mStrips) {
+      if (strip.left >= aStrip.right) {
+        return false;
+      }
+
+      if (strip.right <= aStrip.left) {
+        continue;
+      }
+
+      return true;
+    }
+    return false;
+  }
+
+  bool IntersectStripBounds(Strip& aStrip) const {
+    bool intersected = false;
+
+    int32_t rightMost;
+    for (const Strip& strip : mStrips) {
+      if (strip.left > aStrip.right) {
+        break;
+      }
+
+      if (strip.right <= aStrip.left) {
+        continue;
+      }
+
+      if (!intersected) {
+        // First intersection, this is where the left side begins.
+        aStrip.left = std::max(aStrip.left, strip.left);
+      }
+
+      intersected = true;
+      // Expand to the right for each intersecting strip found.
+      rightMost = std::min(strip.right, aStrip.right);
+    }
+
+    if (intersected) {
+      aStrip.right = rightMost;
+    } else {
+      aStrip.right = aStrip.left = 0;
+    }
+    return intersected;
+  }
+
+  bool ContainsStrip(const Strip& aStrip) const {
+    for (const Strip& strip : mStrips) {
+      if (strip.left > aStrip.left) {
+        return false;
+      }
+
+      if (strip.right >= aStrip.right) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool EqualStrips(const Band& aBand) const {
+    if (mStrips.Length() != aBand.mStrips.Length()) {
+      return false;
+    }
+
+    for (auto iter1 = mStrips.begin(), iter2 = aBand.mStrips.begin();
+         iter1 != mStrips.end(); iter1++, iter2++) {
+      if (*iter1 != *iter2) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  void IntersectStrip(const Strip& aStrip) {
+    size_t i = 0;
+
+    while (i < mStrips.Length()) {
+      Strip& strip = mStrips[i];
+      if (strip.right <= aStrip.left) {
+        mStrips.RemoveElementAt(i);
+        continue;
+      }
+
+      if (strip.left >= aStrip.right) {
+        mStrips.TruncateLength(i);
+        return;
+      }
+
+      strip.left = std::max(aStrip.left, strip.left);
+      strip.right = std::min(aStrip.right, strip.right);
+      i++;
+    }
+  }
+
+  void IntersectStrips(const Band& aOther) {
+    auto iter = mStrips.begin();
+    auto iterOther = aOther.mStrips.begin();
+
+    StripArray newStrips;
+
+    // This function finds the intersection between two sets of strips.
+    while (true) {
+      while (true) {
+        while (iter != mStrips.end() && iter->right <= iterOther->left) {
+          // Increment our current strip until it ends beyond aOther's current
+          // strip.
+          iter++;
+        }
+
+        if (iter == mStrips.end()) {
+          // End of our strips. Done.
+          break;
+        }
+
+        while (iterOther != aOther.mStrips.end() &&
+               iterOther->right <= iter->left) {
+          // Increment aOther's current strip until it lies beyond our current
+          // strip.
+          iterOther++;
+        }
+
+        if (iterOther == aOther.mStrips.end()) {
+          // End of aOther's strips. Done.
+          break;
+        }
+
+        if (iterOther->left < iter->right) {
+          // Intersection!
+          break;
+        }
+      }
+
+      if (iter == mStrips.end() || iterOther == aOther.mStrips.end()) {
+        break;
+      }
+
+      newStrips.AppendElement(Strip(std::max(iter->left, iterOther->left),
+                                    std::min(iterOther->right, iter->right)));
+
+      if (iterOther->right < iter->right) {
+        iterOther++;
+        if (iterOther == aOther.mStrips.end()) {
+          break;
+        }
+      } else {
+        iter++;
+      }
+    }
+
+    mStrips = std::move(newStrips);
+  }
+
+  bool Intersects(const Band& aOther) const {
+    auto iter = mStrips.begin();
+    auto iterOther = aOther.mStrips.begin();
+
+    // This function finds the intersection between two sets of strips.
+    while (true) {
+      while (true) {
+        while (iter != mStrips.end() && iter->right <= iterOther->left) {
+          // Increment our current strip until it ends beyond aOther's current
+          // strip.
+          iter++;
+        }
+
+        if (iter == mStrips.end()) {
+          // End of our strips. Done.
+          break;
+        }
+
+        while (iterOther != aOther.mStrips.end() &&
+               iterOther->right <= iter->left) {
+          // Increment aOther's current strip until it lies beyond our current
+          // strip.
+          iterOther++;
+        }
+
+        if (iterOther == aOther.mStrips.end()) {
+          // End of aOther's strips. Done.
+          break;
+        }
+
+        if (iterOther->left < iter->right) {
+          // Intersection!
+          break;
+        }
+      }
+
+      if (iter == mStrips.end() || iterOther == aOther.mStrips.end()) {
+        break;
+      }
+
+      return true;
+    }
+    return false;
+  }
+
+  void SubStrips(const Band& aOther) {
+    size_t idx = 0;
+    auto iterOther = aOther.mStrips.begin();
+
+    // This function finds the intersection between two sets of strips.
+    while (true) {
+      while (true) {
+        while (idx < mStrips.Length() &&
+               mStrips[idx].right <= iterOther->left) {
+          // Increment our current strip until it ends beyond aOther's current
+          // strip.
+          idx++;
+        }
+
+        if (idx == mStrips.Length()) {
+          // End of our strips. Done.
+          break;
+        }
+
+        while (iterOther != aOther.mStrips.end() &&
+               iterOther->right <= mStrips[idx].left) {
+          // Increment aOther's current strip until it lies beyond our current
+          // strip.
+          iterOther++;
+        }
+
+        if (iterOther == aOther.mStrips.end()) {
+          // End of aOther's strips. Done.
+          break;
+        }
+
+        if (iterOther->left < mStrips[idx].right) {
+          // Intersection!
+          break;
+        }
+      }
+
+      if (idx == mStrips.Length() || iterOther == aOther.mStrips.end()) {
+        break;
+      }
+
+      if (mStrips[idx].left < iterOther->left) {
+        size_t oldIdx = idx;
+        // Our strip starts beyond other's
+        if (mStrips[idx].right > iterOther->right) {
+          // Our strip ends beyond other's as well.
+          Strip newStrip(mStrips[idx]);
+          newStrip.left = iterOther->right;
+          mStrips.InsertElementAt(idx + 1, newStrip);
+          idx++;
+        }
+        mStrips[oldIdx].right = iterOther->left;
+        // Either idx was just incremented, or the current index no longer
+        // intersects with iterOther.
+        continue;
+      } else if (mStrips[idx].right > iterOther->right) {
+        mStrips[idx].left = iterOther->right;
+        // Current strip no longer intersects, continue.
+        iterOther++;
+        if (iterOther == aOther.mStrips.end()) {
+          break;
+        }
+        continue;
+      }
+
+      // Our current strip is completely contained by the other strip.
+      mStrips.RemoveElementAt(idx);
+    }
+  }
+
+  int32_t top;
+  int32_t bottom;
+  StripArray mStrips;
+};
+}  // namespace regiondetails
+
+class nsRegion {
+ public:
+  using Band = regiondetails::Band;
+  using Strip = regiondetails::Strip;
+#ifndef DEBUG
+  using BandArray = regiondetails::UncheckedArray<nsTArray<Band>, Band>;
+  using StripArray = regiondetails::UncheckedArray<AutoTArray<Strip, 2>, Strip>;
+#else
+  using BandArray = nsTArray<Band>;
+  using StripArray = AutoTArray<Strip, 2>;
+#endif
+
+  typedef nsRect RectType;
+  typedef nsPoint PointType;
+  typedef nsMargin MarginType;
+
+  nsRegion() = default;
+  MOZ_IMPLICIT nsRegion(const nsRect& aRect) {
+    mBounds = nsRectAbsolute::FromRect(aRect);
+  }
+  MOZ_IMPLICIT nsRegion(const nsRectAbsolute& aRect) { mBounds = aRect; }
+  explicit nsRegion(mozilla::gfx::ArrayView<pixman_box32_t> aRects) {
+    for (uint32_t i = 0; i < aRects.Length(); i++) {
+      AddRect(BoxToRect(aRects[i]));
+    }
+  }
+
+  nsRegion(const nsRegion& aRegion) { Copy(aRegion); }
+  nsRegion(nsRegion&& aRegion)
+      : mBands(std::move(aRegion.mBands)), mBounds(aRegion.mBounds) {
+    aRegion.SetEmpty();
+  }
+  nsRegion& operator=(nsRegion&& aRegion) {
+    mBands = std::move(aRegion.mBands);
+    mBounds = aRegion.mBounds;
+    aRegion.SetEmpty();
+    return *this;
+  }
+  nsRegion& operator=(const nsRect& aRect) {
+    Copy(aRect);
+    return *this;
+  }
+  nsRegion& operator=(const nsRegion& aRegion) {
+    Copy(aRegion);
+    return *this;
+  }
+  bool operator==(const nsRegion& aRgn) const { return IsEqual(aRgn); }
+  bool operator!=(const nsRegion& aRgn) const { return !(*this == aRgn); }
+
+  friend std::ostream& operator<<(std::ostream& stream, const nsRegion& m);
+  void OutputToStream(std::string aObjName, std::ostream& stream) const;
+
+ private:
+#ifdef DEBUG_REGIONS
+  class OperationStringGenerator {
+   public:
+    virtual ~OperationStringGenerator() = default;
+
+    virtual void OutputOp() = 0;
+  };
+#endif
+ public:
+  void AssertStateInternal() const;
+  void AssertState() const {
+#ifdef DEBUG_REGIONS
+    AssertStateInternal();
+#endif
+  }
+
+ private:
+  void And(BandArray& aOut, const BandArray& aIn1, const BandArray& aIn2) {
+    size_t idx = 0;
+    size_t idxOther = 0;
+
+    // This algorithm essentially forms a new list of bands, by iterating over
+    // both regions' lists of band simultaneously, and building a new band
+    // wherever the two regions intersect.
+    while (true) {
+      while (true) {
+        while (idx != aIn1.Length() && aIn1[idx].bottom <= aIn2[idxOther].top) {
+          // Increment our current band until it ends beyond aOther's current
+          // band.
+          idx++;
+        }
+
+        if (idx == aIn1.Length()) {
+          // This region is out of bands, the other region's future bands are
+          // ignored.
+          break;
+        }
+
+        while (idxOther != aIn2.Length() &&
+               aIn2[idxOther].bottom <= aIn1[idx].top) {
+          // Increment aOther's current band until it ends beyond our current
+          // band.
+          idxOther++;
+        }
+
+        if (idxOther == aIn2.Length()) {
+          // The other region's bands are all processed, all our future bands
+          // are ignored.
+          break;
+        }
+
+        if (aIn2[idxOther].top < aIn1[idx].bottom) {
+          // We know the other band's bottom lies beyond our band's top because
+          // otherwise we would've incremented above. Intersecting bands found.
+          break;
+        }
+      }
+
+      if (idx == aIn1.Length() || idxOther == aIn2.Length()) {
+        // The above loop executed a break because we're done.
+        break;
+      }
+
+      Band newBand(aIn1[idx]);
+      // The new band is the intersection of the two current bands from both
+      // regions.
+      newBand.top = std::max(aIn1[idx].top, aIn2[idxOther].top);
+      newBand.bottom = std::min(aIn1[idx].bottom, aIn2[idxOther].bottom);
+      newBand.IntersectStrips(aIn2[idxOther]);
+
+      if (newBand.mStrips.Length()) {
+        // The intersecting area of the bands had overlapping strips, if it is
+        // identical to the band above it merge, otherwise append.
+        if (aOut.Length() && aOut.LastElement().bottom == newBand.top &&
+            aOut.LastElement().EqualStrips(newBand)) {
+          aOut.LastElement().bottom = newBand.bottom;
+        } else {
+          aOut.AppendElement(std::move(newBand));
+        }
+      }
+
+      if (aIn2[idxOther].bottom < aIn1[idx].bottom) {
+        idxOther++;
+        if (idxOther == aIn2.Length()) {
+          // Since we will access idxOther the next iteration, check if we're
+          // not done.
+          break;
+        }
+      } else {
+        // No need to check here since we do at the beginning of the next
+        // iteration.
+        idx++;
+      }
+    }
+  }
+
+ public:
+  nsRegion& AndWith(const nsRegion& aRegion) {
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorAndWith : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorAndWith(nsRegion& aRegion,
+                                      const nsRegion& aOtherRegion)
+          : mRegion(&aRegion),
+            mRegionCopy(aRegion),
+            mOtherRegion(aOtherRegion) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorAndWith() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegionCopy.OutputToStream("r1", stream);
+        mOtherRegion.OutputToStream("r2", stream);
+        stream << "r1.AndWith(r2);\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegionCopy;
+      nsRegion mOtherRegion;
+    };
+
+    OperationStringGeneratorAndWith opGenerator(*this, aRegion);
+#endif
+    if (mBounds.IsEmpty()) {
+      // Region is empty, stays empty.
+      return *this;
+    }
+
+    if (aRegion.IsEmpty()) {
+      SetEmpty();
+      return *this;
+    }
+
+    if (aRegion.mBands.IsEmpty()) {
+      // Other region is a rect.
+      return AndWith(aRegion.mBounds);
+    }
+
+    if (mBands.IsEmpty()) {
+      mBands.AppendElement(mBounds);
+    }
+
+    BandArray newBands;
+
+    And(newBands, mBands, aRegion.mBands);
+
+    mBands = std::move(newBands);
+    if (!mBands.Length()) {
+      mBounds = nsRectAbsolute();
+    } else {
+      mBounds = CalculateBounds();
+    }
+
+    EnsureSimplified();
+    AssertState();
+    return *this;
+  }
+
+  nsRegion& AndWith(const nsRectAbsolute& aRect) {
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorAndWith : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorAndWith(nsRegion& aRegion,
+                                      const nsRectAbsolute& aRect)
+          : mRegion(&aRegion), mRegionCopy(aRegion), mRect(aRect) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorAndWith() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegionCopy.OutputToStream("r", stream);
+        stream << "r.AndWith(nsRect(" << mRect.X() << ", " << mRect.Y() << ", "
+               << mRect.Width() << ", " << mRect.Height() << "));\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegionCopy;
+      nsRectAbsolute mRect;
+    };
+
+    OperationStringGeneratorAndWith opGenerator(*this, aRect);
+#endif
+    if (aRect.IsEmpty()) {
+      SetEmpty();
+      return *this;
+    }
+
+    if (mBands.IsEmpty()) {
+      mBounds = mBounds.Intersect(aRect);
+      return *this;
+    }
+
+    size_t idx = 0;
+
+    size_t removeStart = 0;
+
+    // This removes all bands that do not intersect with aRect, and intersects
+    // the remaining ones with aRect.
+
+    // Start by figuring out how much to remove from the start.
+    while (idx != mBands.Length() && mBands[idx].bottom <= aRect.Y()) {
+      idx++;
+    }
+
+    // We'll remove these later to avoid needless copying in the array.
+    removeStart = idx;
+
+    while (idx != mBands.Length()) {
+      if (mBands[idx].top >= aRect.YMost()) {
+        mBands.TruncateLength(idx);
+        break;
+      }
+
+      mBands[idx].top = std::max(mBands[idx].top, aRect.Y());
+      mBands[idx].bottom = std::min(mBands[idx].bottom, aRect.YMost());
+
+      mBands[idx].IntersectStrip(Strip(aRect.X(), aRect.XMost()));
+
+      if (!mBands[idx].mStrips.Length()) {
+        mBands.RemoveElementAt(idx);
+      } else {
+        if (idx > removeStart) {
+          CompressBefore(idx);
+        }
+        idx++;
+      }
+    }
+
+    if (removeStart) {
+      mBands.RemoveElementsAt(0, removeStart);
+    }
+
+    if (mBands.Length()) {
+      mBounds = CalculateBounds();
+    } else {
+      mBounds.SetEmpty();
+    }
+    EnsureSimplified();
+    AssertState();
+    return *this;
+  }
+  nsRegion& AndWith(const nsRect& aRect) {
+    return AndWith(nsRectAbsolute::FromRect(aRect));
+  }
+  nsRegion& And(const nsRegion& aRgn1, const nsRegion& aRgn2) {
+    if (&aRgn1 == this) {
+      return AndWith(aRgn2);
+    }
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorAnd : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorAnd(nsRegion& aRegion, const nsRegion& aRegion1,
+                                  const nsRegion& aRegion2)
+          : mRegion(&aRegion), mRegion1(aRegion1), mRegion2(aRegion2) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorAnd() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegion1.OutputToStream("r1", stream);
+        mRegion2.OutputToStream("r2", stream);
+        stream << "nsRegion r3;\nr3.And(r1, r2);\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegion1;
+      nsRegion mRegion2;
+    };
+
+    OperationStringGeneratorAnd opGenerator(*this, aRgn1, aRgn2);
+#endif
+    mBands.Clear();
+
+    if (aRgn1.IsEmpty() || aRgn2.IsEmpty()) {
+      mBounds.SetEmpty();
+      return *this;
+    }
+
+    if (aRgn1.mBands.IsEmpty() && aRgn2.mBands.IsEmpty()) {
+      mBounds = aRgn1.mBounds.Intersect(aRgn2.mBounds);
+      return *this;
+    } else if (aRgn1.mBands.IsEmpty()) {
+      return And(aRgn2, aRgn1.mBounds);
+    } else if (aRgn2.mBands.IsEmpty()) {
+      return And(aRgn1, aRgn2.mBounds);
+    }
+
+    And(mBands, aRgn1.mBands, aRgn2.mBands);
+
+    if (!mBands.Length()) {
+      mBounds = nsRectAbsolute();
+    } else {
+      mBounds = CalculateBounds();
+    }
+
+    EnsureSimplified();
+    AssertState();
+    return *this;
+  }
+  nsRegion& And(const nsRect& aRect, const nsRegion& aRegion) {
+    return And(aRegion, aRect);
+  }
+  nsRegion& And(const nsRegion& aRegion, const nsRectAbsolute& aRect) {
+    if (&aRegion == this) {
+      return AndWith(aRect);
+    }
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorAnd : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorAnd(nsRegion& aThisRegion,
+                                  const nsRegion& aRegion,
+                                  const nsRectAbsolute& aRect)
+          : mThisRegion(&aThisRegion), mRegion(aRegion), mRect(aRect) {
+        aThisRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorAnd() {
+        mThisRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegion.OutputToStream("r", stream);
+        stream << "nsRegion r2;\nr.And(r2, nsRect(" << mRect.X() << ", "
+               << mRect.Y() << ", " << mRect.Width() << ", " << mRect.Height()
+               << "));\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mThisRegion;
+      nsRegion mRegion;
+      nsRectAbsolute mRect;
+    };
+
+    OperationStringGeneratorAnd opGenerator(*this, aRegion, aRect);
+#endif
+    mBands.Clear();
+
+    if (aRect.IsEmpty()) {
+      mBounds.SetEmpty();
+      return *this;
+    }
+
+    if (aRegion.mBands.IsEmpty()) {
+      mBounds = aRegion.mBounds.Intersect(aRect);
+      return *this;
+    }
+
+    size_t idx = 0;
+    const BandArray& bands = aRegion.mBands;
+
+    mBands.SetCapacity(bands.Length() + 3);
+    while (idx != bands.Length()) {
+      // Ignore anything before.
+      if (bands[idx].bottom <= aRect.Y()) {
+        idx++;
+        continue;
+      }
+      // We're done once we've reached the bottom.
+      if (bands[idx].top >= aRect.YMost()) {
+        break;
+      }
+
+      // Now deal with bands actually intersecting the rectangle.
+      Band newBand(bands[idx]);
+      newBand.top = std::max(bands[idx].top, aRect.Y());
+      newBand.bottom = std::min(bands[idx].bottom, aRect.YMost());
+
+      newBand.IntersectStrip(Strip(aRect.X(), aRect.XMost()));
+
+      if (newBand.mStrips.Length()) {
+        if (!mBands.IsEmpty() && newBand.top == mBands.LastElement().bottom &&
+            newBand.EqualStrips(mBands.LastElement())) {
+          mBands.LastElement().bottom = newBand.bottom;
+        } else {
+          mBands.AppendElement(std::move(newBand));
+        }
+      }
+      idx++;
+    }
+
+    if (mBands.Length()) {
+      mBounds = CalculateBounds();
+    } else {
+      mBounds.SetEmpty();
+    }
+
+    EnsureSimplified();
+    AssertState();
+    return *this;
+  }
+  nsRegion& And(const nsRegion& aRegion, const nsRect& aRect) {
+    return And(aRegion, nsRectAbsolute::FromRect(aRect));
+  }
+  nsRegion& And(const nsRect& aRect1, const nsRect& aRect2) {
+    nsRect tmpRect;
+
+    tmpRect.IntersectRect(aRect1, aRect2);
+    return Copy(tmpRect);
+  }
+
+  nsRegion& OrWith(const nsRegion& aOther) {
+    for (RectIterator idx(aOther); !idx.Done(); idx.Next()) {
+      AddRect(idx.GetAbsolute());
+    }
+    return *this;
+  }
+  nsRegion& OrWith(const nsRect& aOther) {
+    AddRect(nsRectAbsolute::FromRect(aOther));
+    return *this;
+  }
+  nsRegion& Or(const nsRegion& aRgn1, const nsRegion& aRgn2) {
+    if (&aRgn1 != this) {
+      *this = aRgn1;
+    }
+    for (RectIterator idx(aRgn2); !idx.Done(); idx.Next()) {
+      AddRect(idx.GetAbsolute());
+    }
+    return *this;
+  }
+  nsRegion& Or(const nsRegion& aRegion, const nsRect& aRect) {
+    if (&aRegion != this) {
+      *this = aRegion;
+    }
+    AddRect(nsRectAbsolute::FromRect(aRect));
+    return *this;
+  }
+  nsRegion& Or(const nsRect& aRect, const nsRegion& aRegion) {
+    return Or(aRegion, aRect);
+  }
+  nsRegion& Or(const nsRect& aRect1, const nsRect& aRect2) {
+    Copy(aRect1);
+    return Or(*this, aRect2);
+  }
+
+  nsRegion& XorWith(const nsRegion& aOther) { return Xor(*this, aOther); }
+  nsRegion& XorWith(const nsRect& aOther) { return Xor(*this, aOther); }
+  nsRegion& Xor(const nsRegion& aRgn1, const nsRegion& aRgn2) {
+    // this could be implemented better if pixman had direct
+    // support for xoring regions.
+    nsRegion p;
+    p.Sub(aRgn1, aRgn2);
+    nsRegion q;
+    q.Sub(aRgn2, aRgn1);
+    return Or(p, q);
+  }
+  nsRegion& Xor(const nsRegion& aRegion, const nsRect& aRect) {
+    return Xor(aRegion, nsRegion(aRect));
+  }
+  nsRegion& Xor(const nsRect& aRect, const nsRegion& aRegion) {
+    return Xor(nsRegion(aRect), aRegion);
+  }
+  nsRegion& Xor(const nsRect& aRect1, const nsRect& aRect2) {
+    return Xor(nsRegion(aRect1), nsRegion(aRect2));
+  }
+
+  nsRegion ToAppUnits(nscoord aAppUnitsPerPixel) const;
+
+  nsRegion& SubWith(const nsRegion& aOther) {
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorSubWith : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorSubWith(nsRegion& aRegion,
+                                      const nsRegion& aOtherRegion)
+          : mRegion(&aRegion),
+            mRegionCopy(aRegion),
+            mOtherRegion(aOtherRegion) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorSubWith() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegionCopy.OutputToStream("r1", stream);
+        mOtherRegion.OutputToStream("r2", stream);
+        stream << "r1.SubWith(r2);\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegionCopy;
+      nsRegion mOtherRegion;
+    };
+
+    OperationStringGeneratorSubWith opGenerator(*this, aOther);
+#endif
+
+    if (mBounds.IsEmpty()) {
+      return *this;
+    }
+
+    if (aOther.mBands.IsEmpty()) {
+      return SubWith(aOther.mBounds);
+    }
+
+    if (mBands.IsEmpty()) {
+      mBands.AppendElement(Band(mBounds));
+    }
+
+    size_t idx = 0;
+    size_t idxOther = 0;
+    while (idx < mBands.Length()) {
+      while (true) {
+        while (idx != mBands.Length() &&
+               mBands[idx].bottom <= aOther.mBands[idxOther].top) {
+          // Increment our current band until it ends beyond aOther's current
+          // band.
+          idx++;
+        }
+
+        if (idx == mBands.Length()) {
+          // This region is out of bands, the other region's future bands are
+          // ignored.
+          break;
+        }
+
+        while (idxOther != aOther.mBands.Length() &&
+               aOther.mBands[idxOther].bottom <= mBands[idx].top) {
+          // Increment aOther's current band until it ends beyond our current
+          // band.
+          idxOther++;
+        }
+
+        if (idxOther == aOther.mBands.Length()) {
+          // The other region's bands are all processed, all our future bands
+          // are ignored.
+          break;
+        }
+
+        if (aOther.mBands[idxOther].top < mBands[idx].bottom) {
+          // We know the other band's bottom lies beyond our band's top because
+          // otherwise we would've incremented above. Intersecting bands found.
+          break;
+        }
+      }
+
+      if (idx == mBands.Length() || idxOther == aOther.mBands.Length()) {
+        // The above loop executed a break because we're done.
+        break;
+      }
+
+      const Band& bandOther = aOther.mBands[idxOther];
+
+      if (!mBands[idx].Intersects(bandOther)) {
+        if (mBands[idx].bottom < bandOther.bottom) {
+          idx++;
+        } else {
+          idxOther++;
+          if (idxOther == aOther.mBands.Length()) {
+            break;
+          }
+        }
+        continue;
+      }
+
+      // These bands actually intersect.
+      if (mBands[idx].top < bandOther.top) {
+        mBands.InsertElementAt(idx + 1, Band(mBands[idx]));
+        mBands[idx].bottom = bandOther.top;
+        idx++;
+        mBands[idx].top = bandOther.top;
+      }
+
+      // mBands[idx].top >= bandOther.top;
+      if (mBands[idx].bottom <= bandOther.bottom) {
+        mBands[idx].SubStrips(bandOther);
+        if (mBands[idx].mStrips.IsEmpty()) {
+          mBands.RemoveElementAt(idx);
+        } else {
+          CompressBefore(idx);
+          idx++;
+          // The band before us just changed, it may be identical now.
+          CompressBefore(idx);
+        }
+        continue;
+      }
+
+      // mBands[idx].bottom > bandOther.bottom
+      Band newBand = mBands[idx];
+      newBand.SubStrips(bandOther);
+
+      if (!newBand.mStrips.IsEmpty()) {
+        mBands.InsertElementAt(idx, newBand);
+        mBands[idx].bottom = bandOther.bottom;
+        CompressBefore(idx);
+        idx++;
+      }
+
+      mBands[idx].top = bandOther.bottom;
+
+      idxOther++;
+      if (idxOther == aOther.mBands.Length()) {
+        break;
+      }
+    }
+
+    if (mBands.IsEmpty()) {
+      mBounds.SetEmpty();
+    } else {
+      mBounds = CalculateBounds();
+    }
+
+    AssertState();
+    EnsureSimplified();
+    return *this;
+  }
+  nsRegion& SubOut(const nsRegion& aOther) { return SubWith(aOther); }
+  nsRegion& SubOut(const nsRect& aOther) { return SubWith(aOther); }
+
+ private:
+  void AppendOrExtend(const Band& aNewBand) {
+    if (aNewBand.mStrips.IsEmpty()) {
+      return;
+    }
+    if (mBands.IsEmpty()) {
+      mBands.AppendElement(aNewBand);
+      return;
+    }
+
+    if (mBands.LastElement().bottom == aNewBand.top &&
+        mBands.LastElement().EqualStrips(aNewBand)) {
+      mBands.LastElement().bottom = aNewBand.bottom;
+    } else {
+      mBands.AppendElement(aNewBand);
+    }
+  }
+  void AppendOrExtend(const Band&& aNewBand) {
+    if (aNewBand.mStrips.IsEmpty()) {
+      return;
+    }
+    if (mBands.IsEmpty()) {
+      mBands.AppendElement(std::move(aNewBand));
+      return;
+    }
+
+    if (mBands.LastElement().bottom == aNewBand.top &&
+        mBands.LastElement().EqualStrips(aNewBand)) {
+      mBands.LastElement().bottom = aNewBand.bottom;
+    } else {
+      mBands.AppendElement(std::move(aNewBand));
+    }
+  }
+
+ public:
+  nsRegion& Sub(const nsRegion& aRgn1, const nsRegion& aRgn2) {
+    if (&aRgn1 == this) {
+      return SubWith(aRgn2);
+    }
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorSub : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorSub(nsRegion& aRegion, const nsRegion& aRgn1,
+                                  const nsRegion& aRgn2)
+          : mRegion(&aRegion), mRegion1(aRgn1), mRegion2(aRgn2) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorSub() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegion1.OutputToStream("r1", stream);
+        mRegion2.OutputToStream("r2", stream);
+        stream << "nsRegion r3;\nr3.Sub(r1, r2);\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegion1;
+      nsRegion mRegion2;
+    };
+
+    OperationStringGeneratorSub opGenerator(*this, aRgn1, aRgn2);
+#endif
+
+    mBands.Clear();
+
+    if (aRgn1.mBounds.IsEmpty()) {
+      mBounds.SetEmpty();
+      return *this;
+    }
+
+    if (aRgn2.mBounds.IsEmpty()) {
+      Copy(aRgn1);
+      return *this;
+    }
+
+    if (aRgn1.mBands.IsEmpty() && aRgn2.mBands.IsEmpty()) {
+      return Sub(aRgn1.mBounds, aRgn2.mBounds);
+    } else if (aRgn1.mBands.IsEmpty()) {
+      return Sub(aRgn1.mBounds, aRgn2);
+    } else if (aRgn2.mBands.IsEmpty()) {
+      return Sub(aRgn1, aRgn2.mBounds);
+    }
+
+    const BandArray& bands1 = aRgn1.mBands;
+    const BandArray& bands2 = aRgn2.mBands;
+
+    size_t idx = 0;
+    size_t idxOther = 0;
+
+    // We iterate the source region's bands, subtracting the other regions bands
+    // from them as we move them into ours.
+    while (idx < bands1.Length()) {
+      while (idxOther < bands2.Length() &&
+             bands2[idxOther].bottom <= bands1[idx].top) {
+        // These other bands are irrelevant as they don't intersect with the
+        // band we're currently processing.
+        idxOther++;
+      }
+      if (idxOther == bands2.Length()) {
+        break;
+      }
+
+      const Band& other = bands2[idxOther];
+
+      // bands2[idxOther].bottom >= bands1[idx].top
+      Band origBand(bands1[idx]);
+      if (other.top >= origBand.bottom) {
+        // No intersecting bands, append and continue.
+        AppendOrExtend(origBand);
+        idx++;
+        continue;
+      }
+
+      // Push a band for an uncovered region above our band.
+      if (origBand.top < other.top) {
+        Band newBand(origBand);
+        newBand.bottom = other.top;
+        AppendOrExtend(std::move(newBand));
+      }
+
+      int32_t lastBottom = std::max(other.top, origBand.top);
+      while (idxOther < bands2.Length() &&
+             bands2[idxOther].top < origBand.bottom) {
+        const Band& other = bands2[idxOther];
+        Band newBand(origBand);
+        newBand.top = std::max(origBand.top, other.top);
+        newBand.bottom = std::min(origBand.bottom, other.bottom);
+
+        // If there was a gap, we need to add the original band there.
+        if (newBand.top > lastBottom) {
+          Band betweenBand(newBand);
+          betweenBand.top = lastBottom;
+          betweenBand.bottom = newBand.top;
+          AppendOrExtend(std::move(betweenBand));
+        }
+
+        lastBottom = newBand.bottom;
+        newBand.SubStrips(other);
+        AppendOrExtend(std::move(newBand));
+        idxOther++;
+      }
+      // Decrement other here so we are back at the last band in region 2
+      // that intersected.
+      idxOther--;
+
+      if (bands2[idxOther].bottom < origBand.bottom) {
+        // The last band in region2 that intersected ended before this one,
+        // we can copy the rest.
+        Band newBand(origBand);
+        newBand.top = bands2[idxOther].bottom;
+        AppendOrExtend(std::move(newBand));
+        idxOther++;
+      }
+      idx++;
+    }
+
+    // Copy any remaining bands, the first one may have to be extended to fit
+    // the last one added before. The rest can be unconditionally appended.
+    if (idx < bands1.Length()) {
+      AppendOrExtend(bands1[idx]);
+      idx++;
+    }
+
+    while (idx < bands1.Length()) {
+      mBands.AppendElement(bands1[idx]);
+      idx++;
+    }
+
+    if (mBands.IsEmpty()) {
+      mBounds.SetEmpty();
+    } else {
+      mBounds = CalculateBounds();
+    }
+
+    AssertState();
+    EnsureSimplified();
+    return *this;
+  }
+
+ private:
+  // Internal helper for executing subtraction.
+  void RunSubtraction(const nsRectAbsolute& aRect) {
+    Strip rectStrip(aRect.X(), aRect.XMost());
+
+    size_t idx = 0;
+
+    while (idx < mBands.Length()) {
+      if (mBands[idx].top >= aRect.YMost()) {
+        return;
+      }
+
+      if (mBands[idx].bottom <= aRect.Y()) {
+        // This band is entirely before aRect, move on.
+        idx++;
+        continue;
+      }
+
+      if (!mBands[idx].Intersects(Strip(aRect.X(), aRect.XMost()))) {
+        // This band does not intersect aRect horizontally. Move on.
+        idx++;
+        continue;
+      }
+
+      // This band intersects with aRect.
+
+      if (mBands[idx].top < aRect.Y()) {
+        // This band starts above the start of aRect, split the band into two
+        // along the intersection, and continue to the next iteration to process
+        // the one that now intersects exactly.
+        auto above = mBands.InsertElementAt(idx, Band(mBands[idx]));
+        above->bottom = aRect.Y();
+        idx++;
+        mBands[idx].top = aRect.Y();
+        // Continue to run the loop for the next band.
+        continue;
+      }
+
+      if (mBands[idx].bottom <= aRect.YMost()) {
+        // This band ends before the end of aRect.
+        mBands[idx].SubStrip(rectStrip);
+        if (mBands[idx].mStrips.Length()) {
+          CompressAdjacentBands(idx);
+        } else {
+          mBands.RemoveElementAt(idx);
+        }
+        continue;
+      }
+
+      // This band extends beyond aRect.
+      Band newBand = mBands[idx];
+      newBand.SubStrip(rectStrip);
+      newBand.bottom = aRect.YMost();
+      mBands[idx].top = aRect.YMost();
+
+      if (newBand.mStrips.Length()) {
+        if (idx && mBands[idx - 1].bottom == newBand.top &&
+            newBand.EqualStrips(mBands[idx - 1])) {
+          mBands[idx - 1].bottom = aRect.YMost();
+        } else {
+          mBands.InsertElementAt(idx, std::move(newBand));
+        }
+      }
+
+      return;
+    }
+  }
+
+ public:
+  nsRegion& SubWith(const nsRectAbsolute& aRect) {
+    if (!mBounds.Intersects(aRect)) {
+      return *this;
+    }
+
+    if (aRect.Contains(mBounds)) {
+      SetEmpty();
+      return *this;
+    }
+
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorSubWith : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorSubWith(nsRegion& aRegion,
+                                      const nsRectAbsolute& aRect)
+          : mRegion(&aRegion), mRegionCopy(aRegion), mRect(aRect) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorSubWith() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegionCopy.OutputToStream("r", stream);
+        stream << "r.SubWith(nsRect(" << mRect.X() << ", " << mRect.Y() << ", "
+               << mRect.Width() << ", " << mRect.Height() << "));\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegionCopy;
+      nsRectAbsolute mRect;
+    };
+
+    OperationStringGeneratorSubWith opGenerator(*this, aRect);
+#endif
+
+    if (mBands.IsEmpty()) {
+      mBands.AppendElement(Band(mBounds));
+    }
+
+    RunSubtraction(aRect);
+
+    if (aRect.X() <= mBounds.X() || aRect.Y() <= mBounds.Y() ||
+        aRect.XMost() >= mBounds.XMost() || aRect.YMost() >= mBounds.YMost()) {
+      mBounds = CalculateBounds();
+    }
+    EnsureSimplified();
+    AssertState();
+    return *this;
+  }
+  nsRegion& Sub(const nsRegion& aRegion, const nsRectAbsolute& aRect) {
+    if (aRect.Contains(aRegion.mBounds)) {
+      SetEmpty();
+      return *this;
+    }
+    if (&aRegion == this) {
+      return SubWith(aRect);
+    }
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorSub : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorSub(nsRegion& aRegion,
+                                  const nsRegion& aRegionOther,
+                                  const nsRectAbsolute& aRect)
+          : mRegion(&aRegion), mRegionOther(aRegionOther), mRect(aRect) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorSub() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegionOther.OutputToStream("r1", stream);
+        stream << "nsRegion r2;\nr2.Sub(r1, nsRect(" << mRect.X() << ", "
+               << mRect.Y() << ", " << mRect.Width() << ", " << mRect.Height()
+               << "));\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegionOther;
+      nsRectAbsolute mRect;
+    };
+
+    OperationStringGeneratorSub opGenerator(*this, aRegion, aRect);
+#endif
+
+    mBands.Clear();
+
+    if (aRegion.mBounds.IsEmpty()) {
+      mBounds.SetEmpty();
+      return *this;
+    }
+
+    if (aRect.IsEmpty()) {
+      Copy(aRegion);
+      return *this;
+    }
+
+    if (aRegion.mBands.IsEmpty()) {
+      Copy(aRegion.mBounds);
+      return SubWith(aRect);
+    }
+
+    const BandArray& bands = aRegion.mBands;
+
+    size_t idx = 0;
+
+    Strip strip(aRect.X(), aRect.XMost());
+
+    mBands.SetCapacity(bands.Length() + 3);
+
+    // Process all bands that lie before aRect.
+    while (idx < bands.Length() && bands[idx].bottom <= aRect.Y()) {
+      mBands.AppendElement(bands[idx]);
+      idx++;
+    }
+
+    // This band's bottom lies beyond aRect.
+    if (idx < bands.Length() && bands[idx].top < aRect.Y()) {
+      Band newBand(bands[idx]);
+      if (bands[idx].Intersects(strip)) {
+        newBand.bottom = aRect.Y();
+      } else {
+        idx++;
+      }
+      mBands.AppendElement(std::move(newBand));
+    }
+
+    // This tracks whether the band when we -exit- the next loop intersected the
+    // rectangle.
+    bool didIntersect = false;
+
+    while (idx < bands.Length() && bands[idx].top < aRect.YMost()) {
+      // Process all bands intersecting with aRect.
+      if (!bands[idx].Intersects(strip)) {
+        AppendOrExtend(bands[idx]);
+        idx++;
+        didIntersect = false;
+        continue;
+      }
+
+      didIntersect = true;
+      Band newBand(bands[idx]);
+      newBand.top = std::max(newBand.top, aRect.Y());
+      newBand.bottom = std::min(newBand.bottom, aRect.YMost());
+      newBand.SubStrip(strip);
+      AppendOrExtend(std::move(newBand));
+      idx++;
+    }
+
+    if (didIntersect) {
+      if (aRect.YMost() < bands[idx - 1].bottom) {
+        // If this band does not intersect the loop above has already added the
+        // whole unmodified band.
+        Band newBand(bands[idx - 1]);
+        newBand.top = aRect.YMost();
+        AppendOrExtend(std::move(newBand));
+      }
+    }
+
+    // Now process all bands beyond aRect.
+    if (idx < bands.Length()) {
+      AppendOrExtend(bands[idx]);
+      idx++;
+    }
+
+    mBands.AppendElements(bands.Elements() + idx, bands.Length() - idx);
+
+    if (mBands.IsEmpty()) {
+      mBounds.SetEmpty();
+    } else {
+      mBounds = CalculateBounds();
+    }
+
+    AssertState();
+    EnsureSimplified();
+    return *this;
+  }
+  nsRegion& SubWith(const nsRect& aRect) {
+    return SubWith(nsRectAbsolute::FromRect(aRect));
+  }
+  nsRegion& Sub(const nsRect& aRect, const nsRegion& aRegion) {
+    Copy(aRect);
+    return SubWith(aRegion);
+  }
+  nsRegion& Sub(const nsRectAbsolute& aRect, const nsRegion& aRegion) {
+    Copy(aRect);
+    return SubWith(aRegion);
+  }
+  nsRegion& Sub(const nsRect& aRect1, const nsRect& aRect2) {
+    Copy(aRect1);
+    return SubWith(aRect2);
+  }
+  nsRegion& Sub(const nsRegion& aRegion, const nsRect& aRect) {
+    return Sub(aRegion, nsRectAbsolute::FromRect(aRect));
+  }
+  nsRegion& Sub(const nsRectAbsolute& aRect1, const nsRectAbsolute& aRect2) {
+    Copy(aRect1);
+    return SubWith(aRect2);
+  }
+
+  /**
+   * Returns true if the given point is inside the region. A region
+   * created from a rect (x=0, y=0, w=100, h=100) will NOT contain
+   * the point x=100, y=100.
+   */
+  bool Contains(int aX, int aY) const {
+    if (mBands.IsEmpty()) {
+      return mBounds.Contains(aX, aY);
+    }
+
+    auto iter = mBands.begin();
+
+    while (iter != mBands.end()) {
+      if (iter->bottom <= aY) {
+        iter++;
+        continue;
+      }
+
+      if (iter->top > aY) {
+        return false;
+      }
+
+      if (iter->ContainsStrip(Strip(aX, aX + 1))) {
+        return true;
+      }
+      return false;
+    }
+    return false;
+  }
+
+  bool Contains(const nsPoint& aPoint) const {
+    return Contains(aPoint.x, aPoint.y);
+  }
+
+  bool Contains(const nsRectAbsolute& aRect) const {
+    if (aRect.IsEmpty()) {
+      return false;
+    }
+
+    if (mBands.IsEmpty()) {
+      return mBounds.Contains(aRect);
+    }
+
+    auto iter = mBands.begin();
+
+    while (iter != mBands.end()) {
+      if (iter->bottom <= aRect.Y()) {
+        iter++;
+        continue;
+      }
+
+      if (iter->top > aRect.Y()) {
+        return false;
+      }
+
+      // Now inside the rectangle.
+      if (!iter->ContainsStrip(Strip(aRect.X(), aRect.XMost()))) {
+        return false;
+      }
+
+      if (iter->bottom >= aRect.YMost()) {
+        return true;
+      }
+
+      int32_t lastY = iter->bottom;
+      iter++;
+      while (iter != mBands.end()) {
+        // Bands do not connect.
+        if (iter->top != lastY) {
+          return false;
+        }
+
+        if (!iter->ContainsStrip(Strip(aRect.X(), aRect.XMost()))) {
+          return false;
+        }
+
+        if (iter->bottom >= aRect.YMost()) {
+          return true;
+        }
+
+        lastY = iter->bottom;
+        iter++;
+      }
+    }
+    return false;
+  }
+  bool Contains(const nsRect& aRect) const {
+    return Contains(nsRectAbsolute::FromRect(aRect));
+  }
+
+  bool Contains(const nsRegion& aRgn) const;
+  bool Intersects(const nsRectAbsolute& aRect) const;
+  bool Intersects(const nsRect& aRect) const {
+    return Intersects(nsRectAbsolute::FromRect(aRect));
+  }
+
+  void MoveBy(int32_t aXOffset, int32_t aYOffset) {
+    MoveBy(nsPoint(aXOffset, aYOffset));
+  }
+  void MoveBy(nsPoint aPt) {
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorMoveBy : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorMoveBy(nsRegion& aRegion, const nsPoint& aPoint)
+          : mRegion(&aRegion), mRegionCopy(aRegion), mPoint(aPoint) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorMoveBy() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegionCopy.OutputToStream("r", stream);
+        stream << "r.MoveBy(nsPoint(" << mPoint.x << ", " << mPoint.y
+               << "));\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegionCopy;
+      nsPoint mPoint;
+    };
+
+    OperationStringGeneratorMoveBy opGenerator(*this, aPt);
+#endif
+
+    mBounds.MoveBy(aPt);
+    for (Band& band : mBands) {
+      band.top += aPt.Y();
+      band.bottom += aPt.Y();
+      for (Strip& strip : band.mStrips) {
+        strip.left += aPt.X();
+        strip.right += aPt.X();
+      }
+    }
+    AssertState();
+  }
+  void SetEmpty() {
+    mBands.Clear();
+    mBounds.SetEmpty();
+  }
+
+  nsRegion MovedBy(int32_t aXOffset, int32_t aYOffset) const {
+    return MovedBy(nsPoint(aXOffset, aYOffset));
+  }
+  nsRegion MovedBy(const nsPoint& aPt) const {
+    nsRegion copy(*this);
+    copy.MoveBy(aPt);
+    return copy;
+  }
+
+  nsRegion Intersect(const nsRegion& aOther) const {
+    nsRegion intersection;
+    intersection.And(*this, aOther);
+    return intersection;
+  }
+
+  void Inflate(const nsMargin& aMargin);
+
+  nsRegion Inflated(const nsMargin& aMargin) const {
+    nsRegion copy(*this);
+    copy.Inflate(aMargin);
+    return copy;
+  }
+
+  bool IsEmpty() const { return mBounds.IsEmpty(); }
+  bool IsComplex() const { return GetNumRects() > 1; }
+  bool IsEqual(const nsRegion& aRegion) const {
+    if (!mBounds.IsEqualInterior(aRegion.mBounds)) {
+      return false;
+    }
+
+    if (mBands.Length() != aRegion.mBands.Length()) {
+      return false;
+    }
+
+    for (auto iter1 = mBands.begin(), iter2 = aRegion.mBands.begin();
+         iter1 != mBands.end(); iter1++, iter2++) {
+      if (iter1->top != iter2->top || iter1->bottom != iter2->bottom ||
+          !iter1->EqualStrips(*iter2)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  uint32_t GetNumRects() const {
+    if (mBands.IsEmpty()) {
+      return mBounds.IsEmpty() ? 0 : 1;
+    }
+
+    uint32_t rects = 0;
+
+    for (const Band& band : mBands) {
+      rects += band.mStrips.Length();
+    }
+
+    return rects;
+  }
+  const nsRect GetBounds() const { return mBounds.ToNSRect(); }
+  const nsRectAbsolute GetAbsoluteBounds() const { return mBounds; }
+  uint64_t Area() const;
+
+  /**
+   * Return this region scaled to a different appunits per pixel (APP) ratio.
+   * This applies nsRect::ScaleToOtherAppUnitsRoundOut/In to each rect of the
+   * region.
+   * @param aFromAPP the APP to scale from
+   * @param aToAPP the APP to scale to
+   * @note this can turn an empty region into a non-empty region
+   */
+  [[nodiscard]] nsRegion ScaleToOtherAppUnitsRoundOut(int32_t aFromAPP,
+                                                      int32_t aToAPP) const;
+  [[nodiscard]] nsRegion ScaleToOtherAppUnitsRoundIn(int32_t aFromAPP,
+                                                     int32_t aToAPP) const;
+  nsRegion& ScaleRoundOut(float aXScale, float aYScale);
+  nsRegion& ScaleInverseRoundOut(float aXScale, float aYScale);
+  nsRegion& Transform(const mozilla::gfx::Matrix4x4& aTransform);
+  nsIntRegion ScaleToOutsidePixels(float aXScale, float aYScale,
+                                   nscoord aAppUnitsPerPixel) const;
+  nsIntRegion ScaleToInsidePixels(float aXScale, float aYScale,
+                                  nscoord aAppUnitsPerPixel) const;
+  nsIntRegion ScaleToNearestPixels(float aXScale, float aYScale,
+                                   nscoord aAppUnitsPerPixel) const;
+  nsIntRegion ToOutsidePixels(nscoord aAppUnitsPerPixel) const;
+  nsIntRegion ToNearestPixels(nscoord aAppUnitsPerPixel) const;
+
+  /**
+   * Gets the largest rectangle contained in the region.
+   * @param aContainingRect if non-empty, we choose a rectangle that
+   * maximizes the area intersecting with aContainingRect (and break ties by
+   * then choosing the largest rectangle overall)
+   */
+  nsRect GetLargestRectangle(const nsRect& aContainingRect = nsRect()) const;
+
+  /**
+   * Make sure the region has at most aMaxRects by adding area to it
+   * if necessary. The simplified region will be a superset of the
+   * original region. The simplified region's bounding box will be
+   * the same as for the current region.
+   */
+  void SimplifyOutward(uint32_t aMaxRects);
+  /**
+   * Simplify the region by adding at most aThreshold area between spans of
+   * rects.  The simplified region will be a superset of the original region.
+   * The simplified region's bounding box will be the same as for the current
+   * region.
+   */
+  void SimplifyOutwardByArea(uint32_t aThreshold);
+  /**
+   * Make sure the region has at most aMaxRects by removing area from
+   * it if necessary. The simplified region will be a subset of the
+   * original region.
+   */
+  void SimplifyInward(uint32_t aMaxRects);
+
+  /**
+   * VisitEdges is a weird kind of function that we use for padding
+   * out surfaces to prevent texture filtering artifacts.
+   * It calls the visitFn callback for each of the exterior edges of
+   * the regions. The top and bottom edges will be expanded 1 pixel
+   * to the left and right if there's an outside corner. The order
+   * the edges are visited is not guaranteed.
+   *
+   * visitFn has a side parameter that can be TOP,BOTTOM,LEFT,RIGHT
+   * and specifies which kind of edge is being visited. x1, y1, x2, y2
+   * are the coordinates of the line. (x1 == x2) || (y1 == y2)
+   */
+  typedef void (*visitFn)(void* closure, VisitSide side, int x1, int y1, int x2,
+                          int y2);
+  void VisitEdges(visitFn, void* closure) const;
+
+  nsCString ToString() const;
+
+  static inline pixman_box32_t RectToBox(const nsRect& aRect) {
+    pixman_box32_t box = {aRect.X(), aRect.Y(), aRect.XMost(), aRect.YMost()};
+    return box;
+  }
+
+  static inline pixman_box32_t RectToBox(const mozilla::gfx::IntRect& aRect) {
+    pixman_box32_t box = {aRect.X(), aRect.Y(), aRect.XMost(), aRect.YMost()};
+    return box;
+  }
+
+ private:
+  nsIntRegion ToPixels(nscoord aAppUnitsPerPixel, bool aOutsidePixels) const;
+
+  nsRegion& Copy(const nsRegion& aRegion) {
+    mBounds = aRegion.mBounds;
+    mBands = aRegion.mBands.Clone();
+    return *this;
+  }
+
+  nsRegion& Copy(const nsRect& aRect) {
+    mBands.Clear();
+    mBounds = nsRectAbsolute::FromRect(aRect);
+    return *this;
+  }
+
+  nsRegion& Copy(const nsRectAbsolute& aRect) {
+    mBands.Clear();
+    mBounds = aRect;
+    return *this;
+  }
+
+  void EnsureSimplified() {
+    if (mBands.Length() == 1 && mBands.begin()->mStrips.Length() == 1) {
+      mBands.Clear();
+    }
+  }
+
+  static inline nsRectAbsolute BoxToRect(const pixman_box32_t& aBox) {
+    return nsRectAbsolute(aBox.x1, aBox.y1, aBox.x2, aBox.y2);
+  }
+
+  void AddRect(const nsRectAbsolute& aRect) {
+#ifdef DEBUG_REGIONS
+    class OperationStringGeneratorAddRect : public OperationStringGenerator {
+     public:
+      OperationStringGeneratorAddRect(nsRegion& aRegion,
+                                      const nsRectAbsolute& aRect)
+          : mRegion(&aRegion), mRegionCopy(aRegion), mRect(aRect) {
+        aRegion.mCurrentOpGenerator = this;
+      }
+      virtual ~OperationStringGeneratorAddRect() {
+        mRegion->mCurrentOpGenerator = nullptr;
+      }
+
+      virtual void OutputOp() override {
+        std::stringstream stream;
+        mRegionCopy.OutputToStream("r", stream);
+        stream << "r.OrWith(nsRect(" << mRect.X() << ", " << mRect.Y() << ", "
+               << mRect.Width() << ", " << mRect.Height() << "));\n";
+        gfxCriticalError() << stream.str();
+      }
+
+     private:
+      nsRegion* mRegion;
+      nsRegion mRegionCopy;
+      nsRectAbsolute mRect;
+    };
+
+    OperationStringGeneratorAddRect opGenerator(*this, aRect);
+#endif
+    if (aRect.IsEmpty()) {
+      return;
+    }
+
+    if (mBands.IsEmpty()) {
+      if (mBounds.IsEmpty()) {
+        mBounds = aRect;
+        return;
+      } else if (mBounds.Contains(aRect)) {
+        return;
+      }
+
+      mBands.AppendElement(Band(mBounds));
+    }
+
+    mBounds = aRect.UnsafeUnion(mBounds);
+
+    size_t idx = 0;
+
+    Strip strip(aRect.X(), aRect.XMost());
+    Band remaining(aRect);
+
+    while (idx != mBands.Length()) {
+      if (mBands[idx].bottom <= remaining.top) {
+        // This band lies wholly above aRect.
+        idx++;
+        continue;
+      }
+
+      if (remaining.top >= remaining.bottom) {
+        AssertState();
+        EnsureSimplified();
+        return;
+      }
+
+      if (mBands[idx].top >= remaining.bottom) {
+        // This band lies wholly below aRect.
+        break;
+      }
+
+      if (mBands[idx].EqualStrips(remaining)) {
+        mBands[idx].top = std::min(mBands[idx].top, remaining.top);
+        // Nothing to do for this band. Just expand.
+        remaining.top = mBands[idx].bottom;
+        CompressBefore(idx);
+        idx++;
+        continue;
+      }
+
+      if (mBands[idx].top > remaining.top) {
+        auto before = mBands.InsertElementAt(idx, remaining);
+        before->bottom = mBands[idx + 1].top;
+        remaining.top = before->bottom;
+        CompressBefore(idx);
+        idx++;
+        CompressBefore(idx);
+        continue;
+      }
+
+      if (mBands[idx].ContainsStrip(strip)) {
+        remaining.top = mBands[idx].bottom;
+        idx++;
+        continue;
+      }
+
+      // mBands[idx].top <= remaining.top.
+
+      if (mBands[idx].top < remaining.top) {
+        auto before = mBands.InsertElementAt(idx, Band(mBands[idx]));
+        before->bottom = remaining.top;
+        idx++;
+        mBands[idx].top = remaining.top;
+        continue;
+      }
+
+      // mBands[idx].top == remaining.top
+      if (mBands[idx].bottom > remaining.bottom) {
+        auto below = mBands.InsertElementAt(idx + 1, Band(mBands[idx]));
+        below->top = remaining.bottom;
+        mBands[idx].bottom = remaining.bottom;
+      }
+
+      mBands[idx].InsertStrip(strip);
+      CompressBefore(idx);
+      remaining.top = mBands[idx].bottom;
+      idx++;
+      CompressBefore(idx);
+    }
+
+    if (remaining.top < remaining.bottom) {
+      // We didn't find any bands that overlapped aRect.
+      if (idx) {
+        if (mBands[idx - 1].bottom == remaining.top &&
+            mBands[idx - 1].EqualStrips(remaining)) {
+          mBands[idx - 1].bottom = remaining.bottom;
+          CompressBefore(idx);
+          AssertState();
+          EnsureSimplified();
+          return;
+        }
+      }
+      mBands.InsertElementAt(idx, remaining);
+      idx++;
+      CompressBefore(idx);
+    } else {
+      CompressBefore(idx);
+    }
+
+    AssertState();
+    EnsureSimplified();
+  }
+
+  // Most callers could probably do this on the fly, if this ever shows up
+  // in profiles we could optimize this.
+  nsRectAbsolute CalculateBounds() const {
+    if (mBands.IsEmpty()) {
+      return mBounds;
+    }
+
+    int32_t top = mBands.begin()->top;
+    int32_t bottom = mBands.LastElement().bottom;
+
+    int32_t leftMost = mBands.begin()->mStrips.begin()->left;
+    int32_t rightMost = mBands.begin()->mStrips.LastElement().right;
+    for (const Band& band : mBands) {
+      leftMost = std::min(leftMost, band.mStrips.begin()->left);
+      rightMost = std::max(rightMost, band.mStrips.LastElement().right);
+    }
+
+    return nsRectAbsolute(leftMost, top, rightMost, bottom);
+  }
+
+  static uint32_t ComputeMergedAreaIncrease(const Band& aTopBand,
+                                            const Band& aBottomBand);
+
+  // Returns true if idx is now referring to the 'next' band
+  bool CompressAdjacentBands(size_t& aIdx) {
+    if ((aIdx + 1) < mBands.Length()) {
+      if (mBands[aIdx + 1].top == mBands[aIdx].bottom &&
+          mBands[aIdx + 1].EqualStrips(mBands[aIdx])) {
+        mBands[aIdx].bottom = mBands[aIdx + 1].bottom;
+        mBands.RemoveElementAt(aIdx + 1);
+      }
+    }
+    if (aIdx) {
+      if (mBands[aIdx - 1].bottom == mBands[aIdx].top &&
+          mBands[aIdx].EqualStrips(mBands[aIdx - 1])) {
+        mBands[aIdx - 1].bottom = mBands[aIdx].bottom;
+        mBands.RemoveElementAt(aIdx);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  void CompressBefore(size_t& aIdx) {
+    if (aIdx && aIdx < mBands.Length()) {
+      if (mBands[aIdx - 1].bottom == mBands[aIdx].top &&
+          mBands[aIdx - 1].EqualStrips(mBands[aIdx])) {
+        mBands[aIdx].top = mBands[aIdx - 1].top;
+        mBands.RemoveElementAt(aIdx - 1);
+        aIdx--;
+      }
+    }
+  }
+
+  BandArray mBands;
+  // Considering we only ever OR with nsRects, the bounds should fit in an
+  // nsRect as well.
+  nsRectAbsolute mBounds;
+#ifdef DEBUG_REGIONS
+  friend class OperationStringGenerator;
+  OperationStringGenerator* mCurrentOpGenerator;
+#endif
+
+ public:
+  class RectIterator {
+    const nsRegion& mRegion;
+    typename BandArray::const_iterator mCurrentBand;
+    typename StripArray::const_iterator mCurrentStrip;
+
+   public:
+    explicit RectIterator(const nsRegion& aRegion)
+        : mRegion(aRegion),
+          mCurrentBand(aRegion.mBands.begin())
+#ifndef DEBUG
+          ,
+          mCurrentStrip(nullptr)
+#endif
+    {
+      mIsDone = mRegion.mBounds.IsEmpty();
+      if (mCurrentBand != aRegion.mBands.end()) {
+        mCurrentStrip = mCurrentBand->mStrips.begin();
+      }
+    }
+
+    bool Done() const { return mIsDone; }
+
+    const nsRect Get() const {
+      if (mRegion.mBands.IsEmpty()) {
+        return mRegion.GetBounds();
+      }
+      return nsRect(mCurrentStrip->left, mCurrentBand->top,
+                    mCurrentStrip->right - mCurrentStrip->left,
+                    mCurrentBand->bottom - mCurrentBand->top);
+    }
+
+    const nsRectAbsolute GetAbsolute() const {
+      if (mRegion.mBands.IsEmpty()) {
+        return mRegion.mBounds;
+      }
+      return nsRectAbsolute(mCurrentStrip->left, mCurrentBand->top,
+                            mCurrentStrip->right, mCurrentBand->bottom);
+    }
+
+    void Next() {
+      if (mRegion.mBands.IsEmpty()) {
+        mIsDone = true;
+        return;
+      }
+
+      mCurrentStrip++;
+      if (mCurrentStrip == mCurrentBand->mStrips.end()) {
+        mCurrentBand++;
+        if (mCurrentBand != mRegion.mBands.end()) {
+          mCurrentStrip = mCurrentBand->mStrips.begin();
+        } else {
+          mIsDone = true;
+        }
+      }
+    }
+
+    bool mIsDone;
+  };
+
+  RectIterator RectIter() const { return RectIterator(*this); }
+};
+
+namespace mozilla {
+namespace gfx {
+
+/**
+ * BaseIntRegions use int32_t coordinates.
+ */
+template <typename Derived, typename Rect, typename Point, typename Margin>
+class BaseIntRegion {
+  friend class ::nsRegion;
+
+  // Give access to all specializations of IntRegionTyped, not just ones that
+  // derive from this specialization of BaseIntRegion.
+  template <typename units>
+  friend class IntRegionTyped;
+
+ public:
+  typedef Rect RectType;
+  typedef Point PointType;
+  typedef Margin MarginType;
+
+  BaseIntRegion() = default;
+  MOZ_IMPLICIT BaseIntRegion(const Rect& aRect) : mImpl(ToRect(aRect)) {}
+  explicit BaseIntRegion(mozilla::gfx::ArrayView<pixman_box32_t> aRects)
+      : mImpl(aRects) {}
+  BaseIntRegion(const BaseIntRegion& aRegion) : mImpl(aRegion.mImpl) {}
+  BaseIntRegion(BaseIntRegion&& aRegion) : mImpl(std::move(aRegion.mImpl)) {}
+  Derived& operator=(const Rect& aRect) {
+    mImpl = ToRect(aRect);
+    return This();
+  }
+  Derived& operator=(const Derived& aRegion) {
+    mImpl = aRegion.mImpl;
+    return This();
+  }
+  Derived& operator=(Derived&& aRegion) {
+    mImpl = std::move(aRegion.mImpl);
+    return This();
+  }
+
+  bool operator==(const Derived& aRgn) const { return IsEqual(aRgn); }
+  bool operator!=(const Derived& aRgn) const { return !(*this == aRgn); }
+
+  friend std::ostream& operator<<(std::ostream& stream, const Derived& m) {
+    return stream << m.mImpl;
+  }
+
+  void AndWith(const Derived& aOther) { And(This(), aOther); }
+  void AndWith(const Rect& aOther) { And(This(), aOther); }
+  Derived& And(const Derived& aRgn1, const Derived& aRgn2) {
+    mImpl.And(aRgn1.mImpl, aRgn2.mImpl);
+    return This();
+  }
+  Derived& And(const Derived& aRegion, const Rect& aRect) {
+    mImpl.And(aRegion.mImpl, ToRect(aRect));
+    return This();
+  }
+  Derived& And(const Rect& aRect, const Derived& aRegion) {
+    return And(aRegion, aRect);
+  }
+  Derived& And(const Rect& aRect1, const Rect& aRect2) {
+    Rect TmpRect;
+
+    TmpRect.IntersectRect(aRect1, aRect2);
+    mImpl = ToRect(TmpRect);
+    return This();
+  }
+
+  Derived& OrWith(const Derived& aOther) { return Or(This(), aOther); }
+  Derived& OrWith(const Rect& aOther) { return Or(This(), aOther); }
+  Derived& Or(const Derived& aRgn1, const Derived& aRgn2) {
+    mImpl.Or(aRgn1.mImpl, aRgn2.mImpl);
+    return This();
+  }
+  Derived& Or(const Derived& aRegion, const Rect& aRect) {
+    mImpl.Or(aRegion.mImpl, ToRect(aRect));
+    return This();
+  }
+  Derived& Or(const Rect& aRect, const Derived& aRegion) {
+    return Or(aRegion, aRect);
+  }
+  Derived& Or(const Rect& aRect1, const Rect& aRect2) {
+    mImpl = ToRect(aRect1);
+    return Or(This(), aRect2);
+  }
+
+  Derived& XorWith(const Derived& aOther) { return Xor(This(), aOther); }
+  Derived& XorWith(const Rect& aOther) { return Xor(This(), aOther); }
+  Derived& Xor(const Derived& aRgn1, const Derived& aRgn2) {
+    mImpl.Xor(aRgn1.mImpl, aRgn2.mImpl);
+    return This();
+  }
+  Derived& Xor(const Derived& aRegion, const Rect& aRect) {
+    mImpl.Xor(aRegion.mImpl, ToRect(aRect));
+    return This();
+  }
+  Derived& Xor(const Rect& aRect, const Derived& aRegion) {
+    return Xor(aRegion, aRect);
+  }
+  Derived& Xor(const Rect& aRect1, const Rect& aRect2) {
+    mImpl = ToRect(aRect1);
+    return Xor(This(), aRect2);
+  }
+
+  Derived& SubOut(const Derived& aOther) { return Sub(This(), aOther); }
+  Derived& SubOut(const Rect& aOther) { return Sub(This(), aOther); }
+  Derived& Sub(const Derived& aRgn1, const Derived& aRgn2) {
+    mImpl.Sub(aRgn1.mImpl, aRgn2.mImpl);
+    return This();
+  }
+  Derived& Sub(const Derived& aRegion, const Rect& aRect) {
+    mImpl.Sub(aRegion.mImpl, ToRect(aRect));
+    return This();
+  }
+  Derived& Sub(const Rect& aRect, const Derived& aRegion) {
+    return Sub(Derived(aRect), aRegion);
+  }
+  Derived& Sub(const Rect& aRect1, const Rect& aRect2) {
+    mImpl = ToRect(aRect1);
+    return Sub(This(), aRect2);
+  }
+
+  /**
+   * Returns true iff the given point is inside the region. A region
+   * created from a rect (x=0, y=0, w=100, h=100) will NOT contain
+   * the point x=100, y=100.
+   */
+  bool Contains(int aX, int aY) const { return mImpl.Contains(aX, aY); }
+  bool Contains(const Point& aPoint) const {
+    return mImpl.Contains(aPoint.x, aPoint.y);
+  }
+  bool Contains(const Rect& aRect) const {
+    return mImpl.Contains(ToRect(aRect));
+  }
+  bool Contains(const Derived& aRgn) const {
+    return mImpl.Contains(aRgn.mImpl);
+  }
+  bool Intersects(const Rect& aRect) const {
+    return mImpl.Intersects(ToRect(aRect));
+  }
+
+  void MoveBy(int32_t aXOffset, int32_t aYOffset) {
+    MoveBy(Point(aXOffset, aYOffset));
+  }
+  void MoveBy(Point aPt) { mImpl.MoveBy(aPt.X(), aPt.Y()); }
+  Derived MovedBy(int32_t aXOffset, int32_t aYOffset) const {
+    return MovedBy(Point(aXOffset, aYOffset));
+  }
+  Derived MovedBy(const Point& aPt) const {
+    Derived copy(This());
+    copy.MoveBy(aPt);
+    return copy;
+  }
+
+  Derived Intersect(const Derived& aOther) const {
+    Derived intersection;
+    intersection.And(This(), aOther);
+    return intersection;
+  }
+
+  void Inflate(const Margin& aMargin) {
+    mImpl.Inflate(
+        nsMargin(aMargin.top, aMargin.right, aMargin.bottom, aMargin.left));
+  }
+  Derived Inflated(const Margin& aMargin) const {
+    Derived copy(This());
+    copy.Inflate(aMargin);
+    return copy;
+  }
+
+  void SetEmpty() { mImpl.SetEmpty(); }
+
+  bool IsEmpty() const { return mImpl.IsEmpty(); }
+  bool IsComplex() const { return mImpl.IsComplex(); }
+  bool IsEqual(const Derived& aRegion) const {
+    return mImpl.IsEqual(aRegion.mImpl);
+  }
+  uint32_t GetNumRects() const { return mImpl.GetNumRects(); }
+  Rect GetBounds() const { return FromRect(mImpl.GetBounds()); }
+  uint64_t Area() const { return mImpl.Area(); }
+  nsRegion ToAppUnits(nscoord aAppUnitsPerPixel) const {
+    nsRegion result;
+    for (auto iter = RectIterator(*this); !iter.Done(); iter.Next()) {
+      nsRect appRect = ::ToAppUnits(iter.Get(), aAppUnitsPerPixel);
+      result.Or(result, appRect);
+    }
+    return result;
+  }
+  Rect GetLargestRectangle(const Rect& aContainingRect = Rect()) const {
+    return FromRect(mImpl.GetLargestRectangle(ToRect(aContainingRect)));
+  }
+
+  Derived& ScaleRoundOut(float aXScale, float aYScale) {
+    mImpl.ScaleRoundOut(aXScale, aYScale);
+    return This();
+  }
+
+  Derived& ScaleInverseRoundOut(float aXScale, float aYScale) {
+    mImpl.ScaleInverseRoundOut(aXScale, aYScale);
+    return This();
+  }
+
+  // Prefer using TransformBy(matrix, region) from UnitTransforms.h,
+  // as applying the transform should typically change the unit system.
+  // TODO(botond): Move this to IntRegionTyped and disable it for
+  //               unit != UnknownUnits.
+  Derived& Transform(const mozilla::gfx::Matrix4x4& aTransform) {
+    mImpl.Transform(aTransform);
+    return This();
+  }
+
+  /**
+   * Make sure the region has at most aMaxRects by adding area to it
+   * if necessary. The simplified region will be a superset of the
+   * original region. The simplified region's bounding box will be
+   * the same as for the current region.
+   */
+  void SimplifyOutward(uint32_t aMaxRects) { mImpl.SimplifyOutward(aMaxRects); }
+  void SimplifyOutwardByArea(uint32_t aThreshold) {
+    mImpl.SimplifyOutwardByArea(aThreshold);
+  }
+  /**
+   * Make sure the region has at most aMaxRects by removing area from
+   * it if necessary. The simplified region will be a subset of the
+   * original region.
+   */
+  void SimplifyInward(uint32_t aMaxRects) { mImpl.SimplifyInward(aMaxRects); }
+
+  typedef void (*visitFn)(void* closure, VisitSide side, int x1, int y1, int x2,
+                          int y2);
+  void VisitEdges(visitFn visit, void* closure) const {
+    mImpl.VisitEdges(visit, closure);
+  }
+
+  nsCString ToString() const { return mImpl.ToString(); }
+
+  class RectIterator {
+    nsRegion::RectIterator mImpl;  // The underlying iterator.
+    mutable Rect mTmp;             // The most recently gotten rectangle.
+
+   public:
+    explicit RectIterator(const BaseIntRegion& aRegion)
+        : mImpl(aRegion.mImpl) {}
+
+    bool Done() const { return mImpl.Done(); }
+
+    const Rect& Get() const {
+      mTmp = FromRect(mImpl.Get());
+      return mTmp;
+    }
+
+    void Next() { mImpl.Next(); }
+  };
+
+  RectIterator RectIter() const { return RectIterator(*this); }
+
+ protected:
+  // Expose enough to derived classes from them to define conversions
+  // between different types of BaseIntRegions.
+  explicit BaseIntRegion(const nsRegion& aImpl) : mImpl(aImpl) {}
+  const nsRegion& Impl() const { return mImpl; }
+
+ private:
+  nsRegion mImpl;
+
+  static nsRect ToRect(const Rect& aRect) {
+    return nsRect(aRect.X(), aRect.Y(), aRect.Width(), aRect.Height());
+  }
+  static Rect FromRect(const nsRect& aRect) {
+    return Rect(aRect.X(), aRect.Y(), aRect.Width(), aRect.Height());
+  }
+
+  Derived& This() { return *static_cast<Derived*>(this); }
+  const Derived& This() const { return *static_cast<const Derived*>(this); }
+};
+
+template <class units>
+class IntRegionTyped
+    : public BaseIntRegion<IntRegionTyped<units>, IntRectTyped<units>,
+                           IntPointTyped<units>, IntMarginTyped<units>> {
+  typedef BaseIntRegion<IntRegionTyped<units>, IntRectTyped<units>,
+                        IntPointTyped<units>, IntMarginTyped<units>>
+      Super;
+
+  // Make other specializations of IntRegionTyped friends.
+  template <typename OtherUnits>
+  friend class IntRegionTyped;
+
+  static_assert(IsPixel<units>::value,
+                "'units' must be a coordinate system tag");
+
+ public:
+  typedef IntRectTyped<units> RectType;
+  typedef IntPointTyped<units> PointType;
+  typedef IntMarginTyped<units> MarginType;
+
+  // Forward constructors.
+  IntRegionTyped() = default;
+  MOZ_IMPLICIT IntRegionTyped(const IntRectTyped<units>& aRect)
+      : Super(aRect) {}
+  IntRegionTyped(const IntRegionTyped& aRegion) : Super(aRegion) {}
+  explicit IntRegionTyped(mozilla::gfx::ArrayView<pixman_box32_t> aRects)
+      : Super(aRects) {}
+  IntRegionTyped(IntRegionTyped&& aRegion) : Super(std::move(aRegion)) {}
+
+  // Assignment operators need to be forwarded as well, otherwise the compiler
+  // will declare deleted ones.
+  IntRegionTyped& operator=(const IntRegionTyped& aRegion) {
+    return Super::operator=(aRegion);
+  }
+  IntRegionTyped& operator=(IntRegionTyped&& aRegion) {
+    return Super::operator=(std::move(aRegion));
+  }
+
+  static IntRegionTyped FromUnknownRegion(const IntRegion& aRegion) {
+    return IntRegionTyped(aRegion.Impl());
+  }
+  IntRegion ToUnknownRegion() const {
+    // Need |this->| because Impl() is defined in a dependent base class.
+    return IntRegion(this->Impl());
+  }
+
+ private:
+  // This is deliberately private, so calling code uses FromUnknownRegion().
+  explicit IntRegionTyped(const nsRegion& aRegion) : Super(aRegion) {}
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+typedef mozilla::gfx::IntRegion nsIntRegion;
+
+#endif
diff --git a/gfx/src/nsRegionFwd.h b/gfx/src/nsRegionFwd.h
new file mode 100644
index 0000000000..b029b35c25
--- /dev/null
+++ b/gfx/src/nsRegionFwd.h
@@ -0,0 +1,27 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsRegionFwd_h__
+#define nsRegionFwd_h__
+
+// Forward declare enough things to define the typedef |nsIntRegion|.
+
+namespace mozilla {
+namespace gfx {
+
+struct UnknownUnits;
+
+template <class units>
+class IntRegionTyped;
+
+typedef IntRegionTyped<UnknownUnits> IntRegion;
+
+}  // namespace gfx
+}  // namespace mozilla
+
+typedef mozilla::gfx::IntRegion nsIntRegion;
+
+#endif
diff --git a/gfx/src/nsSize.h b/gfx/src/nsSize.h
new file mode 100644
index 0000000000..21aa654877
--- /dev/null
+++ b/gfx/src/nsSize.h
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSSIZE_H
+#define NSSIZE_H
+
+#include "nsCoord.h"
+#include "mozilla/gfx/BaseSize.h"
+#include "mozilla/gfx/Point.h"
+
+// Maximum allowable size
+#define NS_MAXSIZE nscoord_MAX
+
+typedef mozilla::gfx::IntSize nsIntSize;
+
+struct nsSize : public mozilla::gfx::BaseSize<nscoord, nsSize> {
+  typedef mozilla::gfx::BaseSize<nscoord, nsSize> Super;
+
+  constexpr nsSize() : Super() {}
+  constexpr nsSize(nscoord aWidth, nscoord aHeight) : Super(aWidth, aHeight) {}
+
+  inline mozilla::gfx::IntSize ScaleToNearestPixels(
+      float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const;
+  inline mozilla::gfx::IntSize ToNearestPixels(nscoord aAppUnitsPerPixel) const;
+
+  /**
+   * Return this size scaled to a different appunits per pixel (APP) ratio.
+   * @param aFromAPP the APP to scale from
+   * @param aToAPP the APP to scale to
+   */
+  [[nodiscard]] inline nsSize ScaleToOtherAppUnits(int32_t aFromAPP,
+                                                   int32_t aToAPP) const;
+};
+
+inline mozilla::gfx::IntSize nsSize::ScaleToNearestPixels(
+    float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const {
+  return mozilla::gfx::IntSize(
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(width, aAppUnitsPerPixel) *
+                     aXScale),
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(height, aAppUnitsPerPixel) *
+                     aYScale));
+}
+
+inline mozilla::gfx::IntSize nsSize::ToNearestPixels(
+    nscoord aAppUnitsPerPixel) const {
+  return ScaleToNearestPixels(1.0f, 1.0f, aAppUnitsPerPixel);
+}
+
+inline nsSize nsSize::ScaleToOtherAppUnits(int32_t aFromAPP,
+                                           int32_t aToAPP) const {
+  if (aFromAPP != aToAPP) {
+    nsSize size;
+    size.width = NSToCoordRound(NSCoordScale(width, aFromAPP, aToAPP));
+    size.height = NSToCoordRound(NSCoordScale(height, aFromAPP, aToAPP));
+    return size;
+  }
+  return *this;
+}
+
+inline nsSize IntSizeToAppUnits(mozilla::gfx::IntSize aSize,
+                                nscoord aAppUnitsPerPixel) {
+  return nsSize(NSIntPixelsToAppUnits(aSize.width, aAppUnitsPerPixel),
+                NSIntPixelsToAppUnits(aSize.height, aAppUnitsPerPixel));
+}
+
+#endif /* NSSIZE_H */
diff --git a/gfx/src/nsThebesFontEnumerator.cpp b/gfx/src/nsThebesFontEnumerator.cpp
new file mode 100644
index 0000000000..9e3b3e2989
--- /dev/null
+++ b/gfx/src/nsThebesFontEnumerator.cpp
@@ -0,0 +1,237 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsThebesFontEnumerator.h"
+#include <stdint.h>              // for uint32_t
+#include "gfxPlatform.h"         // for gfxPlatform
+#include "mozilla/Assertions.h"  // for MOZ_ASSERT_HELPER2
+#include "mozilla/UniquePtr.h"
+#include "mozilla/dom/Promise.h"  // for mozilla::dom::Promise
+#include "nsCOMPtr.h"             // for nsCOMPtr
+#include "nsDebug.h"              // for NS_ENSURE_ARG_POINTER
+#include "nsError.h"              // for NS_OK, NS_FAILED, nsresult
+#include "nsAtom.h"               // for nsAtom, NS_Atomize
+#include "nsID.h"
+#include "nsString.h"  // for nsAutoCString, nsAutoString, etc
+#include "nsTArray.h"  // for nsTArray, nsTArray_Impl, etc
+#include "nscore.h"    // for char16_t, NS_IMETHODIMP
+
+using mozilla::MakeUnique;
+using mozilla::Runnable;
+using mozilla::UniquePtr;
+
+NS_IMPL_ISUPPORTS(nsThebesFontEnumerator, nsIFontEnumerator)
+
+nsThebesFontEnumerator::nsThebesFontEnumerator() = default;
+
+NS_IMETHODIMP
+nsThebesFontEnumerator::EnumerateAllFonts(nsTArray<nsString>& aResult) {
+  return EnumerateFonts(nullptr, nullptr, aResult);
+}
+
+NS_IMETHODIMP
+nsThebesFontEnumerator::EnumerateFonts(const char* aLangGroup,
+                                       const char* aGeneric,
+                                       nsTArray<nsString>& aResult) {
+  nsAutoCString generic;
+  if (aGeneric)
+    generic.Assign(aGeneric);
+  else
+    generic.SetIsVoid(true);
+
+  RefPtr<nsAtom> langGroupAtom;
+  if (aLangGroup) {
+    nsAutoCString lowered;
+    lowered.Assign(aLangGroup);
+    ToLowerCase(lowered);
+    langGroupAtom = NS_Atomize(lowered);
+  }
+
+  return gfxPlatform::GetPlatform()->GetFontList(langGroupAtom, generic,
+                                                 aResult);
+}
+
+struct EnumerateFontsPromise final {
+  explicit EnumerateFontsPromise(mozilla::dom::Promise* aPromise)
+      : mPromise(aPromise) {
+    MOZ_ASSERT(aPromise);
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  RefPtr<mozilla::dom::Promise> mPromise;
+};
+
+class EnumerateFontsResult final : public Runnable {
+ public:
+  EnumerateFontsResult(nsresult aRv,
+                       UniquePtr<EnumerateFontsPromise> aEnumerateFontsPromise,
+                       nsTArray<nsString> aFontList)
+      : Runnable("EnumerateFontsResult"),
+        mRv(aRv),
+        mEnumerateFontsPromise(std::move(aEnumerateFontsPromise)),
+        mFontList(std::move(aFontList)),
+        mWorkerThread(do_GetCurrentThread()) {
+    MOZ_ASSERT(!NS_IsMainThread());
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    if (NS_FAILED(mRv)) {
+      mEnumerateFontsPromise->mPromise->MaybeReject(mRv);
+    } else {
+      mEnumerateFontsPromise->mPromise->MaybeResolve(mFontList);
+    }
+
+    mWorkerThread->Shutdown();
+
+    return NS_OK;
+  }
+
+ private:
+  nsresult mRv;
+  UniquePtr<EnumerateFontsPromise> mEnumerateFontsPromise;
+  nsTArray<nsString> mFontList;
+  nsCOMPtr<nsIThread> mWorkerThread;
+};
+
+class EnumerateFontsTask final : public Runnable {
+ public:
+  EnumerateFontsTask(nsAtom* aLangGroupAtom, const nsAutoCString& aGeneric,
+                     UniquePtr<EnumerateFontsPromise> aEnumerateFontsPromise,
+                     nsIEventTarget* aMainThreadTarget)
+      : Runnable("EnumerateFontsTask"),
+        mLangGroupAtom(aLangGroupAtom),
+        mGeneric(aGeneric),
+        mEnumerateFontsPromise(std::move(aEnumerateFontsPromise)),
+        mMainThreadTarget(aMainThreadTarget) {
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+
+    nsTArray<nsString> fontList;
+
+    nsresult rv = gfxPlatform::GetPlatform()->GetFontList(mLangGroupAtom,
+                                                          mGeneric, fontList);
+    nsCOMPtr<nsIRunnable> runnable = new EnumerateFontsResult(
+        rv, std::move(mEnumerateFontsPromise), std::move(fontList));
+    mMainThreadTarget->Dispatch(runnable.forget());
+
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<nsAtom> mLangGroupAtom;
+  nsAutoCStringN<16> mGeneric;
+  UniquePtr<EnumerateFontsPromise> mEnumerateFontsPromise;
+  RefPtr<nsIEventTarget> mMainThreadTarget;
+};
+
+NS_IMETHODIMP
+nsThebesFontEnumerator::EnumerateAllFontsAsync(
+    JSContext* aCx, JS::MutableHandle<JS::Value> aRval) {
+  return EnumerateFontsAsync(nullptr, nullptr, aCx, aRval);
+}
+
+NS_IMETHODIMP
+nsThebesFontEnumerator::EnumerateFontsAsync(
+    const char* aLangGroup, const char* aGeneric, JSContext* aCx,
+    JS::MutableHandle<JS::Value> aRval) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIGlobalObject> global = xpc::CurrentNativeGlobal(aCx);
+  NS_ENSURE_TRUE(global, NS_ERROR_UNEXPECTED);
+
+  mozilla::ErrorResult errv;
+  RefPtr<mozilla::dom::Promise> promise =
+      mozilla::dom::Promise::Create(global, errv);
+  if (errv.Failed()) {
+    return errv.StealNSResult();
+  }
+
+  auto enumerateFontsPromise = MakeUnique<EnumerateFontsPromise>(promise);
+
+  nsCOMPtr<nsIThread> thread;
+  nsresult rv = NS_NewNamedThread("FontEnumThread", getter_AddRefs(thread));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RefPtr<nsAtom> langGroupAtom;
+  if (aLangGroup) {
+    nsAutoCStringN<16> lowered;
+    lowered.Assign(aLangGroup);
+    ToLowerCase(lowered);
+    langGroupAtom = NS_Atomize(lowered);
+  }
+
+  nsAutoCString generic;
+  if (aGeneric) {
+    generic.Assign(aGeneric);
+  } else {
+    generic.SetIsVoid(true);
+  }
+
+  nsCOMPtr<nsIEventTarget> target =
+      global->EventTargetFor(mozilla::TaskCategory::Other);
+  nsCOMPtr<nsIRunnable> runnable = new EnumerateFontsTask(
+      langGroupAtom, generic, std::move(enumerateFontsPromise), target);
+  thread->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
+
+  if (!ToJSValue(aCx, promise, aRval)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsThebesFontEnumerator::HaveFontFor(const char* aLangGroup, bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  *aResult = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsThebesFontEnumerator::GetDefaultFont(const char* aLangGroup,
+                                       const char* aGeneric,
+                                       char16_t** aResult) {
+  if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aLangGroup) ||
+      NS_WARN_IF(!aGeneric)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  *aResult = nullptr;
+  nsAutoCString defaultFontName(gfxPlatform::GetPlatform()->GetDefaultFontName(
+      nsDependentCString(aLangGroup), nsDependentCString(aGeneric)));
+  if (!defaultFontName.IsEmpty()) {
+    *aResult = UTF8ToNewUnicode(defaultFontName);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsThebesFontEnumerator::GetStandardFamilyName(const char16_t* aName,
+                                              char16_t** aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  NS_ENSURE_ARG_POINTER(aName);
+
+  nsAutoString name(aName);
+  if (name.IsEmpty()) {
+    *aResult = nullptr;
+    return NS_OK;
+  }
+
+  nsAutoCString family;
+  gfxPlatform::GetPlatform()->GetStandardFamilyName(
+      NS_ConvertUTF16toUTF8(aName), family);
+  if (family.IsEmpty()) {
+    *aResult = nullptr;
+    return NS_OK;
+  }
+  *aResult = UTF8ToNewUnicode(family);
+  return NS_OK;
+}
diff --git a/gfx/src/nsThebesFontEnumerator.h b/gfx/src/nsThebesFontEnumerator.h
new file mode 100644
index 0000000000..c0f2d79b68
--- /dev/null
+++ b/gfx/src/nsThebesFontEnumerator.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _NSTHEBESFONTENUMERATOR_H_
+#define _NSTHEBESFONTENUMERATOR_H_
+
+#include "mozilla/Attributes.h"  // for final
+#include "nsIFontEnumerator.h"   // for NS_DECL_NSIFONTENUMERATOR, etc
+#include "nsISupports.h"         // for NS_DECL_ISUPPORTS
+
+class nsThebesFontEnumerator final : public nsIFontEnumerator {
+  ~nsThebesFontEnumerator() = default;
+
+ public:
+  nsThebesFontEnumerator();
+
+  NS_DECL_ISUPPORTS
+
+  NS_DECL_NSIFONTENUMERATOR
+};
+
+#endif /* _NSTHEBESFONTENUMERATOR_H_ */
diff --git a/gfx/src/nsTransform2D.cpp b/gfx/src/nsTransform2D.cpp
new file mode 100644
index 0000000000..655511a626
--- /dev/null
+++ b/gfx/src/nsTransform2D.cpp
@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsTransform2D.h"
+
+void nsTransform2D ::TransformCoord(nscoord* ptX, nscoord* ptY) const {
+  *ptX = NSToCoordRound(*ptX * m00 + m20);
+  *ptY = NSToCoordRound(*ptY * m11 + m21);
+}
+
+void nsTransform2D ::TransformCoord(nscoord* aX, nscoord* aY, nscoord* aWidth,
+                                    nscoord* aHeight) const {
+  nscoord x2 = *aX + *aWidth;
+  nscoord y2 = *aY + *aHeight;
+  TransformCoord(aX, aY);
+  TransformCoord(&x2, &y2);
+  *aWidth = x2 - *aX;
+  *aHeight = y2 - *aY;
+}
diff --git a/gfx/src/nsTransform2D.h b/gfx/src/nsTransform2D.h
new file mode 100644
index 0000000000..fb04f16a12
--- /dev/null
+++ b/gfx/src/nsTransform2D.h
@@ -0,0 +1,103 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsTransform2D_h___
+#define nsTransform2D_h___
+
+#include "nsCoord.h"
+
+class nsTransform2D {
+ private:
+  /**
+   * This represents the following matrix (note that the order of row/column
+   * indices is opposite to usual notation)
+   *
+   *      / m00   0   m20  \
+   * M =  |  0   m11  m21  |
+   *      \  0    0    1   /
+   *
+   * Transformation of a coordinate (x, y) is obtained by setting
+   * v = (x, y, 1)^T and evaluating  M . v
+   **/
+
+  float m00, m11, m20, m21;
+
+ public:
+  nsTransform2D(void) {
+    m20 = m21 = 0.0f;
+    m00 = m11 = 1.0f;
+  }
+
+  ~nsTransform2D(void) = default;
+
+  /**
+   * set this transform to a translation
+   *
+   * @param      tx, x translation
+   * @param      ty, y translation
+   **/
+
+  void SetToTranslate(float tx, float ty) {
+    m00 = m11 = 1.0f;
+    m20 = tx;
+    m21 = ty;
+  }
+
+  /**
+   * get the translation portion of this transform
+   *
+   * @param      pt, Point to return translation values in
+   **/
+
+  void GetTranslationCoord(nscoord* ptX, nscoord* ptY) const {
+    *ptX = NSToCoordRound(m20);
+    *ptY = NSToCoordRound(m21);
+  }
+
+  /**
+   * apply matrix to vector
+   *
+   * @param    pt Point to transform
+   **/
+
+  void TransformCoord(nscoord* ptX, nscoord* ptY) const;
+
+  /**
+   * apply matrix to rect
+   *
+   * @param    rect Rect to transform
+   **/
+
+  void TransformCoord(nscoord* aX, nscoord* aY, nscoord* aWidth,
+                      nscoord* aHeight) const;
+
+  /**
+   * add a scale to a Transform via x, y pair
+   *
+   * @param    ptX x value to add as x scale
+   * @param    ptY y value to add as y scale
+   **/
+
+  void AddScale(float ptX, float ptY) {
+    m00 *= ptX;
+    m11 *= ptY;
+  }
+
+  /**
+   * Set the scale (overriding any previous calls to AddScale, but leaving
+   * any existing translation).
+   *
+   * @param    ptX x value to add as x scale
+   * @param    ptY y value to add as y scale
+   **/
+
+  void SetScale(float ptX, float ptY) {
+    m00 = ptX;
+    m11 = ptY;
+  }
+};
+
+#endif