Adding upstream version 86.0.1.upstream/86.0.1upstream

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

11 files changed, 1934 insertions, 0 deletions

diff --git a/gfx/config/gfxConfig.cpp b/gfx/config/gfxConfig.cpp
new file mode 100644
index 0000000000..9a421f4c57
--- /dev/null
+++ b/gfx/config/gfxConfig.cpp
@@ -0,0 +1,292 @@
+/* -*- 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 "gfxConfig.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Unused.h"
+#include "mozilla/gfx/GPUParent.h"
+#include "mozilla/gfx/GraphicsMessages.h"
+#include "plstr.h"
+
+namespace mozilla {
+namespace gfx {
+
+static UniquePtr<gfxConfig> sConfig;
+
+/* static */ FeatureState& gfxConfig::GetFeature(Feature aFeature) {
+  return sConfig->GetState(aFeature);
+}
+
+/* static */
+bool gfxConfig::IsEnabled(Feature aFeature) {
+  const FeatureState& state = sConfig->GetState(aFeature);
+  return state.IsEnabled();
+}
+
+/* static */
+bool gfxConfig::IsDisabledByDefault(Feature aFeature) {
+  const FeatureState& state = sConfig->GetState(aFeature);
+  return state.DisabledByDefault();
+}
+
+/* static */
+bool gfxConfig::IsForcedOnByUser(Feature aFeature) {
+  const FeatureState& state = sConfig->GetState(aFeature);
+  return state.IsForcedOnByUser();
+}
+
+/* static */
+FeatureStatus gfxConfig::GetValue(Feature aFeature) {
+  const FeatureState& state = sConfig->GetState(aFeature);
+  return state.GetValue();
+}
+
+/* static */
+bool gfxConfig::SetDefault(Feature aFeature, bool aEnable,
+                           FeatureStatus aDisableStatus,
+                           const char* aDisableMessage) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  return state.SetDefault(aEnable, aDisableStatus, aDisableMessage);
+}
+
+/* static */
+void gfxConfig::DisableByDefault(Feature aFeature, FeatureStatus aDisableStatus,
+                                 const char* aDisableMessage,
+                                 const nsACString& aFailureId) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.DisableByDefault(aDisableStatus, aDisableMessage, aFailureId);
+}
+
+/* static */
+void gfxConfig::EnableByDefault(Feature aFeature) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.EnableByDefault();
+}
+
+/* static */
+void gfxConfig::SetDefaultFromPref(Feature aFeature, const char* aPrefName,
+                                   bool aIsEnablePref, bool aDefaultValue) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  return state.SetDefaultFromPref(aPrefName, aIsEnablePref, aDefaultValue);
+}
+
+/* static */
+bool gfxConfig::InitOrUpdate(Feature aFeature, bool aEnable,
+                             FeatureStatus aDisableStatus,
+                             const char* aDisableMessage) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  return state.InitOrUpdate(aEnable, aDisableStatus, aDisableMessage);
+}
+
+/* static */
+void gfxConfig::SetFailed(Feature aFeature, FeatureStatus aStatus,
+                          const char* aMessage, const nsACString& aFailureId) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.SetFailed(aStatus, aMessage, aFailureId);
+}
+
+/* static */
+void gfxConfig::Disable(Feature aFeature, FeatureStatus aStatus,
+                        const char* aMessage, const nsACString& aFailureId) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.Disable(aStatus, aMessage, aFailureId);
+}
+
+/* static */
+void gfxConfig::UserEnable(Feature aFeature, const char* aMessage) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.UserEnable(aMessage);
+}
+
+/* static */
+void gfxConfig::UserForceEnable(Feature aFeature, const char* aMessage) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.UserForceEnable(aMessage);
+}
+
+/* static */
+void gfxConfig::UserDisable(Feature aFeature, const char* aMessage,
+                            const nsACString& aFailureId) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.UserDisable(aMessage, aFailureId);
+}
+
+/* static */
+void gfxConfig::Reenable(Feature aFeature, Fallback aFallback) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  MOZ_ASSERT(IsFeatureStatusFailure(state.GetValue()));
+
+  const char* message = state.GetRuntimeMessage();
+  EnableFallback(aFallback, message);
+  state.SetRuntime(FeatureStatus::Available, nullptr, nsCString());
+}
+
+/* static */
+void gfxConfig::Reset(Feature aFeature) {
+  FeatureState& state = sConfig->GetState(aFeature);
+  state.Reset();
+}
+
+/* static */
+void gfxConfig::Inherit(Feature aFeature, FeatureStatus aStatus) {
+  FeatureState& state = sConfig->GetState(aFeature);
+
+  state.Reset();
+
+  switch (aStatus) {
+    case FeatureStatus::Unused:
+      break;
+    case FeatureStatus::Available:
+      gfxConfig::EnableByDefault(aFeature);
+      break;
+    case FeatureStatus::ForceEnabled:
+      gfxConfig::EnableByDefault(aFeature);
+      gfxConfig::UserForceEnable(aFeature, "Inherited from parent process");
+      break;
+    default:
+      gfxConfig::SetDefault(aFeature, false, aStatus,
+                            "Disabled in parent process");
+      break;
+  }
+}
+
+/* static */
+void gfxConfig::Inherit(EnumSet<Feature> aFeatures,
+                        const DevicePrefs& aDevicePrefs) {
+  for (Feature feature : aFeatures) {
+    FeatureStatus status = FeatureStatus::Unused;
+    switch (feature) {
+      case Feature::HW_COMPOSITING:
+        status = aDevicePrefs.hwCompositing();
+        break;
+      case Feature::D3D11_COMPOSITING:
+        status = aDevicePrefs.d3d11Compositing();
+        break;
+      case Feature::OPENGL_COMPOSITING:
+        status = aDevicePrefs.oglCompositing();
+        break;
+      case Feature::ADVANCED_LAYERS:
+        status = aDevicePrefs.advancedLayers();
+        break;
+      case Feature::DIRECT2D:
+        status = aDevicePrefs.useD2D1();
+        break;
+      case Feature::WEBGPU:
+        status = aDevicePrefs.webGPU();
+        break;
+      default:
+        break;
+    }
+    gfxConfig::Inherit(feature, status);
+  }
+}
+
+/* static */
+bool gfxConfig::UseFallback(Fallback aFallback) {
+  return sConfig->UseFallbackImpl(aFallback);
+}
+
+/* static */
+void gfxConfig::EnableFallback(Fallback aFallback, const char* aMessage) {
+  if (!NS_IsMainThread()) {
+    nsCString message(aMessage);
+    NS_DispatchToMainThread(
+        NS_NewRunnableFunction("gfxConfig::EnableFallback", [=]() -> void {
+          gfxConfig::EnableFallback(aFallback, message.get());
+        }));
+    return;
+  }
+
+  if (XRE_IsGPUProcess()) {
+    nsCString message(aMessage);
+    Unused << GPUParent::GetSingleton()->SendUsedFallback(aFallback, message);
+    return;
+  }
+
+  sConfig->EnableFallbackImpl(aFallback, aMessage);
+}
+
+bool gfxConfig::UseFallbackImpl(Fallback aFallback) const {
+  return !!(mFallbackBits & (uint64_t(1) << uint64_t(aFallback)));
+}
+
+void gfxConfig::EnableFallbackImpl(Fallback aFallback, const char* aMessage) {
+  if (!UseFallbackImpl(aFallback)) {
+    MOZ_ASSERT(mNumFallbackLogEntries < kNumFallbacks);
+
+    FallbackLogEntry& entry = mFallbackLog[mNumFallbackLogEntries];
+    mNumFallbackLogEntries++;
+
+    entry.mFallback = aFallback;
+    PL_strncpyz(entry.mMessage, aMessage, sizeof(entry.mMessage));
+  }
+  mFallbackBits |= (uint64_t(1) << uint64_t(aFallback));
+}
+
+struct FeatureInfo {
+  const char* name;
+  const char* description;
+};
+static const FeatureInfo sFeatureInfo[] = {
+#define FOR_EACH_FEATURE(name, type, desc) {#name, desc},
+    GFX_FEATURE_MAP(FOR_EACH_FEATURE)
+#undef FOR_EACH_FEATURE
+        {nullptr, nullptr}};
+
+/* static */
+void gfxConfig::ForEachFeature(const FeatureIterCallback& aCallback) {
+  for (size_t i = 0; i < kNumFeatures; i++) {
+    FeatureState& state = GetFeature(static_cast<Feature>(i));
+    if (!state.IsInitialized()) {
+      continue;
+    }
+
+    aCallback(sFeatureInfo[i].name, sFeatureInfo[i].description, state);
+  }
+}
+
+static const char* sFallbackNames[] = {
+#define FOR_EACH_FALLBACK(name) #name,
+    GFX_FALLBACK_MAP(FOR_EACH_FALLBACK)
+#undef FOR_EACH_FALLBACK
+        nullptr};
+
+/* static  */
+void gfxConfig::ForEachFallback(const FallbackIterCallback& aCallback) {
+  sConfig->ForEachFallbackImpl(aCallback);
+}
+
+void gfxConfig::ForEachFallbackImpl(const FallbackIterCallback& aCallback) {
+  for (size_t i = 0; i < mNumFallbackLogEntries; i++) {
+    const FallbackLogEntry& entry = mFallbackLog[i];
+    aCallback(sFallbackNames[size_t(entry.mFallback)], entry.mMessage);
+  }
+}
+
+/* static */ const nsCString& gfxConfig::GetFailureId(Feature aFeature) {
+  const FeatureState& state = sConfig->GetState(aFeature);
+  return state.GetFailureId();
+}
+
+/* static */
+void gfxConfig::ImportChange(Feature aFeature,
+                             const Maybe<FeatureFailure>& aChange) {
+  if (aChange.isNothing()) {
+    return;
+  }
+
+  const FeatureFailure& failure = aChange.ref();
+  gfxConfig::SetFailed(aFeature, failure.status(), failure.message().get(),
+                       failure.failureId());
+}
+
+/* static */
+void gfxConfig::Init() { sConfig = mozilla::MakeUnique<gfxConfig>(); }
+
+/* static */
+void gfxConfig::Shutdown() { sConfig = nullptr; }
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/config/gfxConfig.h b/gfx/config/gfxConfig.h
new file mode 100644
index 0000000000..c6a39d373e
--- /dev/null
+++ b/gfx/config/gfxConfig.h
@@ -0,0 +1,224 @@
+/* -*- 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_config_gfxConfig_h
+#define mozilla_gfx_config_gfxConfig_h
+
+#include <functional>
+#include "gfxFeature.h"
+#include "gfxFallback.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/EnumSet.h"
+#include "mozilla/Maybe.h"
+
+namespace mozilla {
+namespace gfx {
+
+// Defined in GraphicsMessages.ipdlh.
+class DevicePrefs;
+class FeatureFailure;
+
+// Manages the history and state of a graphics feature. The flow of a feature
+// is:
+//   - A default value, set by all.js, or gfxPlatform.
+//   - A user value, set by an external value or user pref.
+//   - An environment value, determined by system/hardware factors or
+//   nsIGfxInfo.
+//   - A runtime value, determined by any failures encountered after enabling
+//     the feature.
+//
+// Each state change for a feature is recorded in this class.
+class gfxConfig {
+ public:
+  // Return the full state history of a feature.
+  static FeatureState& GetFeature(Feature aFeature);
+
+  // Query whether a parameter is enabled, taking into account any user or
+  // runtime overrides. The algorithm works as follow:
+  //
+  //  1. If a runtime decision disabled the feature, return false.
+  //  2. If the user force-enabled the feature, return true.
+  //  3. If the environment disabled the feature, return false.
+  //  4. If the user specified a decision, return it.
+  //  5. Return the base setting for the feature.
+  static bool IsEnabled(Feature aFeature);
+
+  // Query the history of a parameter. ForcedOnByUser returns whether or not
+  // the user specifically used a "force" preference to enable the parameter.
+  // IsDisabledByDefault returns whether or not the initial status of the
+  // feature, before adding user prefs and runtime decisions, was disabled.
+  static bool IsForcedOnByUser(Feature aFeature);
+
+  // This returns true if the feature was disabled by default, or was never
+  // initialized to begin with.
+  static bool IsDisabledByDefault(Feature aFeature);
+
+  // Query the status value of a parameter. This is computed similar to
+  // IsEnabled:
+  //
+  //  1. If a runtime failure was set, return it.
+  //  2. If the user force-enabled the feature, return ForceEnabled.
+  //  3. If an environment status was set, return it.
+  //  4. If a user status was set, return it.
+  //  5. Return the default status.
+  static FeatureStatus GetValue(Feature aFeature);
+
+  // Reset the entire state of a feature.
+  static void Reset(Feature aFeature);
+
+  // Initialize the base value of a parameter. The return value is aEnable.
+  static bool SetDefault(Feature aFeature, bool aEnable,
+                         FeatureStatus aDisableStatus,
+                         const char* aDisableMessage);
+  static void DisableByDefault(Feature aFeature, FeatureStatus aDisableStatus,
+                               const char* aDisableMessage,
+                               const nsACString& aFailureId = ""_ns);
+  static void EnableByDefault(Feature aFeature);
+
+  // Inherit a computed value from another process.
+  static void Inherit(Feature aFeature, FeatureStatus aStatus);
+
+  // Inherit a set of computed values from another process.
+  static void Inherit(EnumSet<Feature> aFeatures,
+                      const DevicePrefs& aDevicePrefs);
+
+  // Set a environment status that overrides both the default and user
+  // statuses; this should be used to disable features based on system
+  // or hardware problems that can be determined up-front. The only
+  // status that can override this decision is the user force-enabling
+  // the feature.
+  static void Disable(Feature aFeature, FeatureStatus aStatus,
+                      const char* aMessage,
+                      const nsACString& aFailureId = ""_ns);
+
+  // Given a preference name, infer the default value and whether or not the
+  // user has changed it. |aIsEnablePref| specifies whether or not the pref
+  // is intended to enable a feature (true), or disable it (false).
+  static void SetDefaultFromPref(Feature aFeature, const char* aPrefName,
+                                 bool aIsEnablePref, bool aDefaultValue);
+
+  // Disable a parameter based on a runtime decision. This permanently
+  // disables the feature, since runtime decisions override all other
+  // decisions.
+  static void SetFailed(Feature aFeature, FeatureStatus aStatus,
+                        const char* aMessage,
+                        const nsACString& aFailureId = ""_ns);
+
+  // Force a feature to be disabled permanently. This is the same as
+  // SetFailed(), but the name may be clearer depending on the context.
+  static void ForceDisable(Feature aFeature, FeatureStatus aStatus,
+                           const char* aMessage,
+                           const nsACString& aFailureId = ""_ns) {
+    SetFailed(aFeature, aStatus, aMessage, aFailureId);
+  }
+
+  // Convenience helpers for SetFailed().
+  static bool MaybeSetFailed(Feature aFeature, bool aEnable,
+                             FeatureStatus aDisableStatus,
+                             const char* aDisableMessage,
+                             const nsACString& aFailureId = ""_ns) {
+    if (!aEnable) {
+      SetFailed(aFeature, aDisableStatus, aDisableMessage, aFailureId);
+      return false;
+    }
+    return true;
+  }
+
+  // Convenience helper for SetFailed().
+  static bool MaybeSetFailed(Feature aFeature, FeatureStatus aStatus,
+                             const char* aDisableMessage,
+                             const nsACString& aFailureId = ""_ns) {
+    return MaybeSetFailed(aFeature,
+                          (aStatus != FeatureStatus::Available &&
+                           aStatus != FeatureStatus::ForceEnabled),
+                          aStatus, aDisableMessage, aFailureId);
+  }
+
+  // Re-enables a feature that was previously disabled, by attaching it to a
+  // fallback. The fallback inherits the message that was used for disabling
+  // the feature. This can be used, for example, when D3D11 fails at runtime
+  // but we acquire a second, successful device with WARP.
+  static void Reenable(Feature aFeature, Fallback aFallback);
+
+  // Same as SetDefault, except if the feature already has a default value
+  // set, the new value will be set as a runtime value. This is useful for
+  // when the base value can change (for example, via an update from the
+  // parent process).
+  static bool InitOrUpdate(Feature aFeature, bool aEnable,
+                           FeatureStatus aDisableStatus,
+                           const char* aDisableMessage);
+
+  // Set a user status that overrides the base value (but not runtime value)
+  // of a parameter.
+  static void UserEnable(Feature aFeature, const char* aMessage);
+  static void UserForceEnable(Feature aFeature, const char* aMessage);
+  static void UserDisable(Feature aFeature, const char* aMessage,
+                          const nsACString& aFailureId = ""_ns);
+
+  // Query whether a fallback has been toggled.
+  static bool UseFallback(Fallback aFallback);
+
+  // Add a log entry denoting that a given fallback had to be used. This can
+  // be called from any thread in the UI or GPU process.
+  static void EnableFallback(Fallback aFallback, const char* aMessage);
+
+  // Run a callback for each initialized FeatureState.
+  typedef std::function<void(const char* aName, const char* aDescription,
+                             FeatureState& aFeature)>
+      FeatureIterCallback;
+  static void ForEachFeature(const FeatureIterCallback& aCallback);
+
+  // Run a callback for each enabled fallback.
+  typedef std::function<void(const char* aName, const char* aMsg)>
+      FallbackIterCallback;
+  static void ForEachFallback(const FallbackIterCallback& aCallback);
+
+  // Get the most descriptive failure id message for this feature.
+  static const nsCString& GetFailureId(Feature aFeature);
+
+  static void ImportChange(Feature aFeature,
+                           const Maybe<FeatureFailure>& aChange);
+
+  static void Init();
+  static void Shutdown();
+
+ private:
+  void ForEachFallbackImpl(const FallbackIterCallback& aCallback);
+
+ private:
+  FeatureState& GetState(Feature aFeature) {
+    MOZ_ASSERT(size_t(aFeature) < kNumFeatures);
+    return mFeatures[size_t(aFeature)];
+  }
+  const FeatureState& GetState(Feature aFeature) const {
+    MOZ_ASSERT(size_t(aFeature) < kNumFeatures);
+    return mFeatures[size_t(aFeature)];
+  }
+
+  bool UseFallbackImpl(Fallback aFallback) const;
+  void EnableFallbackImpl(Fallback aFallback, const char* aMessage);
+
+ private:
+  static const size_t kNumFeatures = size_t(Feature::NumValues);
+  static const size_t kNumFallbacks = size_t(Fallback::NumValues);
+
+ private:
+  FeatureState mFeatures[kNumFeatures];
+  uint64_t mFallbackBits;
+
+ private:
+  struct FallbackLogEntry {
+    Fallback mFallback;
+    char mMessage[80];
+  };
+
+  FallbackLogEntry mFallbackLog[kNumFallbacks];
+  size_t mNumFallbackLogEntries;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_config_gfxConfig_h
diff --git a/gfx/config/gfxConfigManager.cpp b/gfx/config/gfxConfigManager.cpp
new file mode 100644
index 0000000000..a9df4b2e19
--- /dev/null
+++ b/gfx/config/gfxConfigManager.cpp
@@ -0,0 +1,410 @@
+/* -*- 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/gfx/gfxConfigManager.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Services.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_layers.h"
+#include "gfxConfig.h"
+#include "gfxPlatform.h"
+#include "nsIGfxInfo.h"
+#include "nsPrintfCString.h"
+#include "nsXULAppAPI.h"
+
+#ifdef XP_WIN
+#  include "mozilla/WindowsVersion.h"
+#  include "mozilla/gfx/DeviceManagerDx.h"
+#  include "mozilla/gfx/DisplayConfigWindows.h"
+#endif
+
+namespace mozilla {
+namespace gfx {
+
+void gfxConfigManager::Init() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  EmplaceUserPref("gfx.webrender.compositor", mWrCompositorEnabled);
+  mWrForceEnabled = gfxPlatform::WebRenderPrefEnabled();
+  mWrForceDisabled = StaticPrefs::gfx_webrender_force_disabled_AtStartup();
+  mWrSoftwareForceEnabled = StaticPrefs::gfx_webrender_software_AtStartup();
+  mWrCompositorForceEnabled =
+      StaticPrefs::gfx_webrender_compositor_force_enabled_AtStartup();
+  mGPUProcessAllowSoftware =
+      StaticPrefs::layers_gpu_process_allow_software_AtStartup();
+  mWrPartialPresent =
+      StaticPrefs::gfx_webrender_max_partial_present_rects_AtStartup() > 0;
+#ifdef XP_WIN
+  mWrForceAngle = StaticPrefs::gfx_webrender_force_angle_AtStartup();
+  mWrForceAngleNoGPUProcess = StaticPrefs::
+      gfx_webrender_enabled_no_gpu_process_with_angle_win_AtStartup();
+  mWrDCompWinEnabled =
+      Preferences::GetBool("gfx.webrender.dcomp-win.enabled", false);
+#endif
+
+  mWrEnvForceEnabled = gfxPlatform::WebRenderEnvvarEnabled();
+  mWrEnvForceDisabled = gfxPlatform::WebRenderEnvvarDisabled();
+
+#ifdef XP_WIN
+  DeviceManagerDx::Get()->CheckHardwareStretchingSupport(mHwStretchingSupport);
+  mScaledResolution = HasScaledResolution();
+  mIsWin10OrLater = IsWin10OrLater();
+  mWrCompositorDCompRequired = true;
+#else
+  ++mHwStretchingSupport.mBoth;
+#endif
+
+#ifdef MOZ_WIDGET_GTK
+  mDisableHwCompositingNoWr = true;
+  mXRenderEnabled = mozilla::Preferences::GetBool("gfx.xrender.enabled");
+#endif
+
+#ifdef NIGHTLY_BUILD
+  mIsNightly = true;
+#endif
+  mSafeMode = gfxPlatform::InSafeMode();
+
+  mGfxInfo = services::GetGfxInfo();
+
+  mFeatureWr = &gfxConfig::GetFeature(Feature::WEBRENDER);
+  mFeatureWrQualified = &gfxConfig::GetFeature(Feature::WEBRENDER_QUALIFIED);
+  mFeatureWrCompositor = &gfxConfig::GetFeature(Feature::WEBRENDER_COMPOSITOR);
+  mFeatureWrAngle = &gfxConfig::GetFeature(Feature::WEBRENDER_ANGLE);
+  mFeatureWrDComp = &gfxConfig::GetFeature(Feature::WEBRENDER_DCOMP_PRESENT);
+  mFeatureWrPartial = &gfxConfig::GetFeature(Feature::WEBRENDER_PARTIAL);
+  mFeatureWrSoftware = &gfxConfig::GetFeature(Feature::WEBRENDER_SOFTWARE);
+
+  mFeatureHwCompositing = &gfxConfig::GetFeature(Feature::HW_COMPOSITING);
+#ifdef XP_WIN
+  mFeatureD3D11HwAngle = &gfxConfig::GetFeature(Feature::D3D11_HW_ANGLE);
+#endif
+  mFeatureGPUProcess = &gfxConfig::GetFeature(Feature::GPU_PROCESS);
+}
+
+void gfxConfigManager::EmplaceUserPref(const char* aPrefName,
+                                       Maybe<bool>& aValue) {
+  if (Preferences::HasUserValue(aPrefName)) {
+    aValue.emplace(Preferences::GetBool(aPrefName, false));
+  }
+}
+
+void gfxConfigManager::ConfigureFromBlocklist(long aFeature,
+                                              FeatureState* aFeatureState) {
+  MOZ_ASSERT(aFeatureState);
+
+  nsCString blockId;
+  int32_t status;
+  if (!NS_SUCCEEDED(mGfxInfo->GetFeatureStatus(aFeature, blockId, &status))) {
+    aFeatureState->Disable(FeatureStatus::BlockedNoGfxInfo, "gfxInfo is broken",
+                           "FEATURE_FAILURE_NO_GFX_INFO"_ns);
+
+  } else {
+    if (status != nsIGfxInfo::FEATURE_STATUS_OK) {
+      aFeatureState->Disable(FeatureStatus::Blocklisted,
+                             "Blocklisted by gfxInfo", blockId);
+    }
+  }
+}
+
+void gfxConfigManager::ConfigureWebRenderSoftware() {
+  MOZ_ASSERT(mFeatureWrSoftware);
+
+  mFeatureWrSoftware->EnableByDefault();
+
+  // Note that for testing in CI, software WebRender uses gfx.webrender.software
+  // to force enable WebRender Software. As a result, we need to prefer that
+  // over the MOZ_WEBRENDER envvar which is used to otherwise force on WebRender
+  // (hardware). See bug 1656811.
+  if (mWrSoftwareForceEnabled) {
+    mFeatureWrSoftware->UserForceEnable("Force enabled by pref");
+  } else if (mWrForceEnabled || mWrEnvForceEnabled) {
+    mFeatureWrSoftware->UserDisable(
+        "User force-enabled full WR",
+        "FEATURE_FAILURE_USER_FORCE_ENABLED_FULL_WR"_ns);
+  } else if (mWrForceDisabled || mWrEnvForceDisabled) {
+    // If the user set the pref to force-disable, let's do that. This
+    // will override all the other enabling prefs
+    mFeatureWrSoftware->UserDisable("User force-disabled WR",
+                                    "FEATURE_FAILURE_USER_FORCE_DISABLED"_ns);
+  }
+
+  nsCString failureId;
+  int32_t status;
+  if (NS_FAILED(mGfxInfo->GetFeatureStatus(
+          nsIGfxInfo::FEATURE_WEBRENDER_SOFTWARE, failureId, &status))) {
+    mFeatureWrSoftware->Disable(FeatureStatus::BlockedNoGfxInfo,
+                                "gfxInfo is broken",
+                                "FEATURE_FAILURE_WR_NO_GFX_INFO"_ns);
+    return;
+  }
+
+  switch (status) {
+    case nsIGfxInfo::FEATURE_ALLOW_ALWAYS:
+    case nsIGfxInfo::FEATURE_ALLOW_QUALIFIED:
+      break;
+    case nsIGfxInfo::FEATURE_DENIED:
+      mFeatureWrSoftware->Disable(FeatureStatus::Denied, "Not on allowlist",
+                                  failureId);
+      break;
+    default:
+      mFeatureWrSoftware->Disable(FeatureStatus::Blocklisted,
+                                  "No qualified hardware", failureId);
+      break;
+    case nsIGfxInfo::FEATURE_STATUS_OK:
+      MOZ_ASSERT_UNREACHABLE("We should still be rolling out WebRender!");
+      mFeatureWrSoftware->Disable(FeatureStatus::Blocked,
+                                  "Not controlled by rollout", failureId);
+      break;
+  }
+}
+
+void gfxConfigManager::ConfigureWebRenderQualified() {
+  MOZ_ASSERT(mFeatureWrQualified);
+  MOZ_ASSERT(mFeatureWrCompositor);
+
+  mFeatureWrQualified->EnableByDefault();
+
+  nsCString failureId;
+  int32_t status;
+  if (NS_FAILED(mGfxInfo->GetFeatureStatus(nsIGfxInfo::FEATURE_WEBRENDER,
+                                           failureId, &status))) {
+    mFeatureWrQualified->Disable(FeatureStatus::BlockedNoGfxInfo,
+                                 "gfxInfo is broken",
+                                 "FEATURE_FAILURE_WR_NO_GFX_INFO"_ns);
+    return;
+  }
+
+  switch (status) {
+    case nsIGfxInfo::FEATURE_ALLOW_ALWAYS:
+    case nsIGfxInfo::FEATURE_ALLOW_QUALIFIED:
+      break;
+    case nsIGfxInfo::FEATURE_DENIED:
+      mFeatureWrQualified->Disable(FeatureStatus::Denied, "Not on allowlist",
+                                   failureId);
+      break;
+    default:
+      mFeatureWrQualified->Disable(FeatureStatus::Blocklisted,
+                                   "No qualified hardware", failureId);
+      break;
+    case nsIGfxInfo::FEATURE_STATUS_OK:
+      MOZ_ASSERT_UNREACHABLE("We should still be rolling out WebRender!");
+      mFeatureWrQualified->Disable(FeatureStatus::Blocked,
+                                   "Not controlled by rollout", failureId);
+      break;
+  }
+
+  if (!mIsNightly) {
+    // Disable WebRender if we don't have DirectComposition
+    nsAutoString adapterVendorID;
+    mGfxInfo->GetAdapterVendorID(adapterVendorID);
+    if (adapterVendorID == u"0x8086") {
+      bool mixed;
+      int32_t maxRefreshRate = mGfxInfo->GetMaxRefreshRate(&mixed);
+      if (maxRefreshRate > 75) {
+        mFeatureWrQualified->Disable(FeatureStatus::Blocked,
+                                     "Monitor refresh rate too high",
+                                     "REFRESH_RATE_TOO_HIGH"_ns);
+      }
+    } else if (adapterVendorID == u"0x10de") {
+      bool mixed = false;
+      int32_t maxRefreshRate = mGfxInfo->GetMaxRefreshRate(&mixed);
+      if (maxRefreshRate > 60 && mixed) {
+        mFeatureWrQualified->Disable(FeatureStatus::Blocked,
+                                     "Monitor refresh rate too high/mixed",
+                                     "NVIDIA_REFRESH_RATE_MIXED"_ns);
+      }
+    }
+  }
+}
+
+void gfxConfigManager::ConfigureWebRender() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(mFeatureWr);
+  MOZ_ASSERT(mFeatureWrQualified);
+  MOZ_ASSERT(mFeatureWrCompositor);
+  MOZ_ASSERT(mFeatureWrAngle);
+  MOZ_ASSERT(mFeatureWrDComp);
+  MOZ_ASSERT(mFeatureWrPartial);
+  MOZ_ASSERT(mFeatureWrSoftware);
+  MOZ_ASSERT(mFeatureHwCompositing);
+  MOZ_ASSERT(mFeatureGPUProcess);
+
+  // Initialize WebRender native compositor usage
+  mFeatureWrCompositor->SetDefaultFromPref("gfx.webrender.compositor", true,
+                                           false, mWrCompositorEnabled);
+
+  if (mWrCompositorForceEnabled) {
+    mFeatureWrCompositor->UserForceEnable("Force enabled by pref");
+  }
+
+  ConfigureFromBlocklist(nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR,
+                         mFeatureWrCompositor);
+
+  // Disable native compositor when hardware stretching is not supported. It is
+  // for avoiding a problem like Bug 1618370.
+  // XXX Is there a better check for Bug 1618370?
+  if (!mHwStretchingSupport.IsFullySupported() && mScaledResolution) {
+    nsPrintfCString failureId(
+        "FEATURE_FAILURE_NO_HARDWARE_STRETCHING_B%uW%uF%uN%uE%u",
+        mHwStretchingSupport.mBoth, mHwStretchingSupport.mWindowOnly,
+        mHwStretchingSupport.mFullScreenOnly, mHwStretchingSupport.mNone,
+        mHwStretchingSupport.mError);
+    mFeatureWrCompositor->Disable(FeatureStatus::Unavailable,
+                                  "No hardware stretching support", failureId);
+  }
+
+  ConfigureWebRenderSoftware();
+  ConfigureWebRenderQualified();
+
+  mFeatureWr->EnableByDefault();
+
+  // envvar works everywhere; note that we need this for testing in CI.
+  // Prior to bug 1523788, the `prefEnabled` check was only done on Nightly,
+  // so as to prevent random users from easily enabling WebRender on
+  // unqualified hardware in beta/release.
+  if (mWrSoftwareForceEnabled) {
+    MOZ_ASSERT(mFeatureWrSoftware->IsEnabled());
+    mFeatureWr->UserDisable("User force-enabled software WR",
+                            "FEATURE_FAILURE_USER_FORCE_ENABLED_SW_WR"_ns);
+  } else if (mWrEnvForceEnabled) {
+    mFeatureWr->UserForceEnable("Force enabled by envvar");
+  } else if (mWrForceEnabled) {
+    mFeatureWr->UserForceEnable("Force enabled by pref");
+  } else if (mWrForceDisabled || mWrEnvForceDisabled) {
+    // If the user set the pref to force-disable, let's do that. This
+    // will override all the other enabling prefs
+    // (gfx.webrender.enabled, gfx.webrender.all, and
+    // gfx.webrender.all.qualified).
+    mFeatureWr->UserDisable("User force-disabled WR",
+                            "FEATURE_FAILURE_USER_FORCE_DISABLED"_ns);
+  }
+
+  if (!mFeatureWrQualified->IsEnabled()) {
+    // No qualified hardware. If we haven't allowed software fallback,
+    // then we need to disable WR.
+    mFeatureWr->Disable(FeatureStatus::Disabled, "Not qualified",
+                        "FEATURE_FAILURE_NOT_QUALIFIED"_ns);
+  }
+
+  // HW_COMPOSITING being disabled implies interfacing with the GPU might break
+  if (!mFeatureHwCompositing->IsEnabled()) {
+    mFeatureWr->ForceDisable(FeatureStatus::UnavailableNoHwCompositing,
+                             "Hardware compositing is disabled",
+                             "FEATURE_FAILURE_WEBRENDER_NEED_HWCOMP"_ns);
+  }
+
+  if (mSafeMode) {
+    mFeatureWr->ForceDisable(FeatureStatus::UnavailableInSafeMode,
+                             "Safe-mode is enabled",
+                             "FEATURE_FAILURE_SAFE_MODE"_ns);
+    mFeatureWrSoftware->ForceDisable(FeatureStatus::UnavailableInSafeMode,
+                                     "Safe-mode is enabled",
+                                     "FEATURE_FAILURE_SAFE_MODE"_ns);
+  }
+
+  if (mXRenderEnabled) {
+    // XRender and WebRender don't play well together. XRender is disabled by
+    // default. If the user opts into it don't enable webrender.
+    mFeatureWr->ForceDisable(FeatureStatus::Blocked, "XRender is enabled",
+                             "FEATURE_FAILURE_XRENDER"_ns);
+    mFeatureWrSoftware->ForceDisable(FeatureStatus::Blocked,
+                                     "XRender is enabled",
+                                     "FEATURE_FAILURE_XRENDER"_ns);
+  }
+
+  mFeatureWrAngle->EnableByDefault();
+  if (mFeatureD3D11HwAngle) {
+    if (mWrForceAngle) {
+      if (!mFeatureD3D11HwAngle->IsEnabled()) {
+        mFeatureWrAngle->ForceDisable(FeatureStatus::UnavailableNoAngle,
+                                      "ANGLE is disabled",
+                                      mFeatureD3D11HwAngle->GetFailureId());
+      } else if (!mFeatureGPUProcess->IsEnabled() &&
+                 !mWrForceAngleNoGPUProcess) {
+        // WebRender with ANGLE relies on the GPU process when on Windows
+        mFeatureWrAngle->ForceDisable(
+            FeatureStatus::UnavailableNoGpuProcess, "GPU Process is disabled",
+            "FEATURE_FAILURE_GPU_PROCESS_DISABLED"_ns);
+      } else if (!mFeatureWr->IsEnabled() && !mFeatureWrSoftware->IsEnabled()) {
+        mFeatureWrAngle->ForceDisable(FeatureStatus::Unavailable,
+                                      "WebRender disabled",
+                                      "FEATURE_FAILURE_WR_DISABLED"_ns);
+      }
+    } else {
+      mFeatureWrAngle->Disable(FeatureStatus::Disabled, "ANGLE is not forced",
+                               "FEATURE_FAILURE_ANGLE_NOT_FORCED"_ns);
+    }
+  } else {
+    mFeatureWrAngle->Disable(FeatureStatus::Unavailable, "OS not supported",
+                             "FEATURE_FAILURE_OS_NOT_SUPPORTED"_ns);
+  }
+
+  if (mWrForceAngle && mFeatureWr->IsEnabled() &&
+      !mFeatureWrAngle->IsEnabled()) {
+    // Ensure we disable WebRender if ANGLE is unavailable and it is required.
+    mFeatureWr->ForceDisable(FeatureStatus::UnavailableNoAngle,
+                             "ANGLE is disabled",
+                             mFeatureWrAngle->GetFailureId());
+  }
+
+  if (!mFeatureWr->IsEnabled() && mDisableHwCompositingNoWr) {
+    if (mFeatureHwCompositing->IsEnabled()) {
+      // Hardware compositing should be disabled by default if we aren't using
+      // WebRender. We had to check if it is enabled at all, because it may
+      // already have been forced disabled (e.g. safe mode, headless). It may
+      // still be forced on by the user, and if so, this should have no effect.
+      mFeatureHwCompositing->Disable(FeatureStatus::Blocked,
+                                     "Acceleration blocked by platform", ""_ns);
+    }
+
+    if (!mFeatureHwCompositing->IsEnabled() &&
+        mFeatureGPUProcess->IsEnabled() && !mGPUProcessAllowSoftware) {
+      // We have neither WebRender nor OpenGL, we don't allow the GPU process
+      // for basic compositor, and it wasn't disabled already.
+      mFeatureGPUProcess->Disable(FeatureStatus::Unavailable,
+                                  "Hardware compositing is unavailable.",
+                                  ""_ns);
+    }
+  }
+
+  mFeatureWrDComp->EnableByDefault();
+  if (!mWrDCompWinEnabled) {
+    mFeatureWrDComp->UserDisable("User disabled via pref",
+                                 "FEATURE_FAILURE_DCOMP_PREF_DISABLED"_ns);
+  }
+
+  if (!mIsWin10OrLater) {
+    // XXX relax win version to windows 8.
+    mFeatureWrDComp->Disable(FeatureStatus::Unavailable,
+                             "Requires Windows 10 or later",
+                             "FEATURE_FAILURE_DCOMP_NOT_WIN10"_ns);
+  }
+
+  mFeatureWrDComp->MaybeSetFailed(
+      mFeatureWr->IsEnabled(), FeatureStatus::Unavailable, "Requires WebRender",
+      "FEATURE_FAILURE_DCOMP_NOT_WR"_ns);
+  mFeatureWrDComp->MaybeSetFailed(mFeatureWrAngle->IsEnabled(),
+                                  FeatureStatus::Unavailable, "Requires ANGLE",
+                                  "FEATURE_FAILURE_DCOMP_NOT_ANGLE"_ns);
+
+  if (!mFeatureWrDComp->IsEnabled() && mWrCompositorDCompRequired) {
+    mFeatureWrCompositor->ForceDisable(FeatureStatus::Unavailable,
+                                       "No DirectComposition usage",
+                                       mFeatureWrDComp->GetFailureId());
+  }
+
+  // Initialize WebRender partial present config.
+  // Partial present is used only when WebRender compositor is not used.
+  if (mWrPartialPresent) {
+    if (mFeatureWr->IsEnabled() || mFeatureWrSoftware->IsEnabled()) {
+      mFeatureWrPartial->EnableByDefault();
+    }
+  }
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/config/gfxConfigManager.h b/gfx/config/gfxConfigManager.h
new file mode 100644
index 0000000000..ee4324d8ca
--- /dev/null
+++ b/gfx/config/gfxConfigManager.h
@@ -0,0 +1,110 @@
+/* -*- 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_config_gfxConfigManager_h
+#define mozilla_gfx_config_gfxConfigManager_h
+
+#include "gfxFeature.h"
+#include "gfxTypes.h"
+#include "nsCOMPtr.h"
+
+class nsIGfxInfo;
+
+namespace mozilla {
+namespace gfx {
+
+class gfxConfigManager {
+ public:
+  gfxConfigManager()
+      : mFeatureWr(nullptr),
+        mFeatureWrQualified(nullptr),
+        mFeatureWrCompositor(nullptr),
+        mFeatureWrAngle(nullptr),
+        mFeatureWrDComp(nullptr),
+        mFeatureWrPartial(nullptr),
+        mFeatureWrSoftware(nullptr),
+        mFeatureHwCompositing(nullptr),
+        mFeatureD3D11HwAngle(nullptr),
+        mFeatureGPUProcess(nullptr),
+        mWrForceEnabled(false),
+        mWrForceDisabled(false),
+        mWrSoftwareForceEnabled(false),
+        mWrCompositorForceEnabled(false),
+        mWrForceAngle(false),
+        mWrForceAngleNoGPUProcess(false),
+        mWrDCompWinEnabled(false),
+        mWrCompositorDCompRequired(false),
+        mWrPartialPresent(false),
+        mGPUProcessAllowSoftware(false),
+        mXRenderEnabled(false),
+        mWrEnvForceEnabled(false),
+        mWrEnvForceDisabled(false),
+        mScaledResolution(false),
+        mDisableHwCompositingNoWr(false),
+        mIsNightly(false),
+        mSafeMode(false),
+        mIsWin10OrLater(false) {}
+
+  void Init();
+
+  void ConfigureWebRender();
+  void ConfigureFromBlocklist(long aFeature, FeatureState* aFeatureState);
+
+ protected:
+  void EmplaceUserPref(const char* aPrefName, Maybe<bool>& aValue);
+  void ConfigureWebRenderQualified();
+  void ConfigureWebRenderSoftware();
+
+  nsCOMPtr<nsIGfxInfo> mGfxInfo;
+
+  FeatureState* mFeatureWr;
+  FeatureState* mFeatureWrQualified;
+  FeatureState* mFeatureWrCompositor;
+  FeatureState* mFeatureWrAngle;
+  FeatureState* mFeatureWrDComp;
+  FeatureState* mFeatureWrPartial;
+  FeatureState* mFeatureWrSoftware;
+
+  FeatureState* mFeatureHwCompositing;
+  FeatureState* mFeatureD3D11HwAngle;
+  FeatureState* mFeatureGPUProcess;
+
+  /**
+   * Prefs
+   */
+  Maybe<bool> mWrCompositorEnabled;
+  bool mWrForceEnabled;
+  bool mWrForceDisabled;
+  bool mWrSoftwareForceEnabled;
+  bool mWrCompositorForceEnabled;
+  bool mWrForceAngle;
+  bool mWrForceAngleNoGPUProcess;
+  bool mWrDCompWinEnabled;
+  bool mWrCompositorDCompRequired;
+  bool mWrPartialPresent;
+  bool mGPUProcessAllowSoftware;
+  bool mXRenderEnabled;
+
+  /**
+   * Environment variables
+   */
+  bool mWrEnvForceEnabled;
+  bool mWrEnvForceDisabled;
+
+  /**
+   * System support
+   */
+  HwStretchingSupport mHwStretchingSupport;
+  bool mScaledResolution;
+  bool mDisableHwCompositingNoWr;
+  bool mIsNightly;
+  bool mSafeMode;
+  bool mIsWin10OrLater;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_config_gfxConfigParams_h
diff --git a/gfx/config/gfxFallback.h b/gfx/config/gfxFallback.h
new file mode 100644
index 0000000000..6875558856
--- /dev/null
+++ b/gfx/config/gfxFallback.h
@@ -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/. */
+#ifndef mozilla_gfx_config_gfxFallback_h
+#define mozilla_gfx_config_gfxFallback_h
+
+#include <stdint.h>
+#include "gfxTelemetry.h"
+
+namespace mozilla {
+namespace gfx {
+
+#define GFX_FALLBACK_MAP(_)        \
+  /* Name */                       \
+  _(NO_CONSTANT_BUFFER_OFFSETTING) \
+  /* Add new entries above this comment */
+
+enum class Fallback : uint32_t {
+#define MAKE_ENUM(name) name,
+  GFX_FALLBACK_MAP(MAKE_ENUM)
+#undef MAKE_ENUM
+      NumValues
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_config_gfxFallback_h
diff --git a/gfx/config/gfxFeature.cpp b/gfx/config/gfxFeature.cpp
new file mode 100644
index 0000000000..8391cadb91
--- /dev/null
+++ b/gfx/config/gfxFeature.cpp
@@ -0,0 +1,307 @@
+/* -*- 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 "gfxFeature.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/Sprintf.h"
+#include "nsString.h"
+
+namespace mozilla {
+namespace gfx {
+
+bool FeatureState::IsEnabled() const {
+  return IsInitialized() && IsFeatureStatusSuccess(GetValue());
+}
+
+FeatureStatus FeatureState::GetValue() const {
+  if (!IsInitialized()) {
+    return FeatureStatus::Unused;
+  }
+
+  if (mRuntime.mStatus != FeatureStatus::Unused) {
+    return mRuntime.mStatus;
+  }
+  if (mUser.mStatus == FeatureStatus::ForceEnabled) {
+    return FeatureStatus::ForceEnabled;
+  }
+  if (mEnvironment.mStatus != FeatureStatus::Unused) {
+    return mEnvironment.mStatus;
+  }
+  if (mUser.mStatus != FeatureStatus::Unused) {
+    return mUser.mStatus;
+  }
+  return mDefault.mStatus;
+}
+
+bool FeatureState::SetDefault(bool aEnable, FeatureStatus aDisableStatus,
+                              const char* aDisableMessage) {
+  if (!aEnable) {
+    DisableByDefault(aDisableStatus, aDisableMessage,
+                     "FEATURE_FAILURE_DISABLED"_ns);
+    return false;
+  }
+  EnableByDefault();
+  return true;
+}
+
+void FeatureState::SetDefaultFromPref(const char* aPrefName, bool aIsEnablePref,
+                                      bool aDefaultValue,
+                                      Maybe<bool> aUserValue) {
+  bool baseValue =
+      Preferences::GetBool(aPrefName, aDefaultValue, PrefValueKind::Default);
+  SetDefault(baseValue == aIsEnablePref, FeatureStatus::Disabled,
+             "Disabled by default");
+
+  if (aUserValue) {
+    if (*aUserValue == aIsEnablePref) {
+      nsCString message("Enabled via ");
+      message.AppendASCII(aPrefName);
+      UserEnable(message.get());
+    } else {
+      nsCString message("Disabled via ");
+      message.AppendASCII(aPrefName);
+      UserDisable(message.get(), "FEATURE_FAILURE_PREF_OFF"_ns);
+    }
+  }
+}
+
+void FeatureState::SetDefaultFromPref(const char* aPrefName, bool aIsEnablePref,
+                                      bool aDefaultValue) {
+  Maybe<bool> userValue;
+  if (Preferences::HasUserValue(aPrefName)) {
+    userValue.emplace(Preferences::GetBool(aPrefName, aDefaultValue));
+  }
+
+  SetDefaultFromPref(aPrefName, aIsEnablePref, aDefaultValue, userValue);
+}
+
+bool FeatureState::InitOrUpdate(bool aEnable, FeatureStatus aDisableStatus,
+                                const char* aDisableMessage) {
+  if (!IsInitialized()) {
+    return SetDefault(aEnable, aDisableStatus, aDisableMessage);
+  }
+  return MaybeSetFailed(aEnable, aDisableStatus, aDisableMessage, nsCString());
+}
+
+void FeatureState::UserEnable(const char* aMessage) {
+  AssertInitialized();
+  SetUser(FeatureStatus::Available, aMessage, nsCString());
+}
+
+void FeatureState::UserForceEnable(const char* aMessage) {
+  AssertInitialized();
+  SetUser(FeatureStatus::ForceEnabled, aMessage, nsCString());
+}
+
+void FeatureState::UserDisable(const char* aMessage,
+                               const nsACString& aFailureId) {
+  AssertInitialized();
+  SetUser(FeatureStatus::Disabled, aMessage, aFailureId);
+}
+
+void FeatureState::Disable(FeatureStatus aStatus, const char* aMessage,
+                           const nsACString& aFailureId) {
+  AssertInitialized();
+
+  // We should never bother setting an environment status to "enabled," since
+  // it could override an explicit user decision to disable it.
+  MOZ_ASSERT(IsFeatureStatusFailure(aStatus));
+
+  SetEnvironment(aStatus, aMessage, aFailureId);
+}
+
+void FeatureState::SetFailed(FeatureStatus aStatus, const char* aMessage,
+                             const nsACString& aFailureId) {
+  AssertInitialized();
+
+  // We should never bother setting a runtime status to "enabled," since it
+  // could override an explicit user decision to disable it.
+  MOZ_ASSERT(IsFeatureStatusFailure(aStatus));
+
+  SetRuntime(aStatus, aMessage, aFailureId);
+}
+
+bool FeatureState::MaybeSetFailed(bool aEnable, FeatureStatus aStatus,
+                                  const char* aMessage,
+                                  const nsACString& aFailureId) {
+  if (!aEnable) {
+    SetFailed(aStatus, aMessage, aFailureId);
+    return false;
+  }
+  return true;
+}
+
+bool FeatureState::MaybeSetFailed(FeatureStatus aStatus, const char* aMessage,
+                                  const nsACString& aFailureId) {
+  return MaybeSetFailed(IsFeatureStatusSuccess(aStatus), aStatus, aMessage,
+                        aFailureId);
+}
+
+bool FeatureState::DisabledByDefault() const {
+  return mDefault.mStatus != FeatureStatus::Available;
+}
+
+bool FeatureState::IsForcedOnByUser() const {
+  AssertInitialized();
+  return mUser.mStatus == FeatureStatus::ForceEnabled;
+}
+
+void FeatureState::EnableByDefault() {
+  // User/runtime decisions should not have been made yet.
+  MOZ_ASSERT(!mUser.IsInitialized());
+  MOZ_ASSERT(!mEnvironment.IsInitialized());
+  MOZ_ASSERT(!mRuntime.IsInitialized());
+
+  mDefault.Set(FeatureStatus::Available);
+}
+
+void FeatureState::DisableByDefault(FeatureStatus aStatus, const char* aMessage,
+                                    const nsACString& aFailureId) {
+  // User/runtime decisions should not have been made yet.
+  MOZ_ASSERT(!mUser.IsInitialized());
+  MOZ_ASSERT(!mEnvironment.IsInitialized());
+  MOZ_ASSERT(!mRuntime.IsInitialized());
+
+  // Make sure that when disabling we actually use a failure status.
+  MOZ_ASSERT(IsFeatureStatusFailure(aStatus));
+
+  mDefault.Set(aStatus, aMessage, aFailureId);
+}
+
+void FeatureState::SetUser(FeatureStatus aStatus, const char* aMessage,
+                           const nsACString& aFailureId) {
+  // Default decision must have been made, but not runtime or environment.
+  MOZ_ASSERT(mDefault.IsInitialized());
+  MOZ_ASSERT(!mEnvironment.IsInitialized());
+  MOZ_ASSERT(!mRuntime.IsInitialized());
+
+  mUser.Set(aStatus, aMessage, aFailureId);
+}
+
+void FeatureState::SetEnvironment(FeatureStatus aStatus, const char* aMessage,
+                                  const nsACString& aFailureId) {
+  // Default decision must have been made, but not runtime.
+  MOZ_ASSERT(mDefault.IsInitialized());
+  MOZ_ASSERT(!mRuntime.IsInitialized());
+
+  mEnvironment.Set(aStatus, aMessage, aFailureId);
+}
+
+void FeatureState::SetRuntime(FeatureStatus aStatus, const char* aMessage,
+                              const nsACString& aFailureId) {
+  AssertInitialized();
+
+  mRuntime.Set(aStatus, aMessage, aFailureId);
+}
+
+const char* FeatureState::GetRuntimeMessage() const {
+  MOZ_ASSERT(IsFeatureStatusFailure(mRuntime.mStatus));
+  return mRuntime.mMessage;
+}
+
+void FeatureState::ForEachStatusChange(
+    const StatusIterCallback& aCallback) const {
+  AssertInitialized();
+
+  aCallback("default", mDefault.mStatus, mDefault.MessageOrNull(),
+            mDefault.FailureId());
+  if (mUser.IsInitialized()) {
+    aCallback("user", mUser.mStatus, mUser.Message(), mDefault.FailureId());
+  }
+  if (mEnvironment.IsInitialized()) {
+    aCallback("env", mEnvironment.mStatus, mEnvironment.Message(),
+              mDefault.FailureId());
+  }
+  if (mRuntime.IsInitialized()) {
+    aCallback("runtime", mRuntime.mStatus, mRuntime.Message(),
+              mDefault.FailureId());
+  }
+}
+
+const char* FeatureState::GetFailureMessage() const {
+  AssertInitialized();
+  MOZ_ASSERT(!IsEnabled());
+
+  if (mRuntime.mStatus != FeatureStatus::Unused &&
+      IsFeatureStatusFailure(mRuntime.mStatus)) {
+    return mRuntime.mMessage;
+  }
+  if (mEnvironment.mStatus != FeatureStatus::Unused &&
+      IsFeatureStatusFailure(mEnvironment.mStatus)) {
+    return mEnvironment.mMessage;
+  }
+  if (mUser.mStatus != FeatureStatus::Unused &&
+      IsFeatureStatusFailure(mUser.mStatus)) {
+    return mUser.mMessage;
+  }
+
+  MOZ_ASSERT(IsFeatureStatusFailure(mDefault.mStatus));
+  return mDefault.mMessage;
+}
+
+const nsCString& FeatureState::GetFailureId() const {
+  MOZ_ASSERT(!IsEnabled());
+
+  if (mRuntime.mStatus != FeatureStatus::Unused) {
+    return mRuntime.mFailureId;
+  }
+  if (mEnvironment.mStatus != FeatureStatus::Unused) {
+    return mEnvironment.mFailureId;
+  }
+  if (mUser.mStatus != FeatureStatus::Unused) {
+    return mUser.mFailureId;
+  }
+
+  return mDefault.mFailureId;
+}
+
+nsCString FeatureState::GetStatusAndFailureIdString() const {
+  nsCString status;
+  auto value = GetValue();
+  switch (value) {
+    case FeatureStatus::Blocklisted:
+    case FeatureStatus::Disabled:
+    case FeatureStatus::Unavailable:
+    case FeatureStatus::UnavailableNoAngle:
+    case FeatureStatus::Blocked:
+      status.AppendPrintf("%s:%s", FeatureStatusToString(value),
+                          GetFailureId().get());
+      break;
+    default:
+      status.Append(FeatureStatusToString(value));
+      break;
+  }
+
+  return status;
+}
+
+void FeatureState::Reset() {
+  mDefault.Set(FeatureStatus::Unused);
+  mUser.Set(FeatureStatus::Unused);
+  mEnvironment.Set(FeatureStatus::Unused);
+  mRuntime.Set(FeatureStatus::Unused);
+}
+
+void FeatureState::Instance::Set(FeatureStatus aStatus) {
+  mStatus = aStatus;
+  mMessage[0] = '\0';
+  mFailureId.Truncate();
+}
+
+void FeatureState::Instance::Set(FeatureStatus aStatus, const char* aMessage,
+                                 const nsACString& aFailureId) {
+  mStatus = aStatus;
+  if (aMessage) {
+    SprintfLiteral(mMessage, "%s", aMessage);
+  } else {
+    mMessage[0] = '\0';
+  }
+  mFailureId.Assign(aFailureId);
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/config/gfxFeature.h b/gfx/config/gfxFeature.h
new file mode 100644
index 0000000000..9ef1658b7e
--- /dev/null
+++ b/gfx/config/gfxFeature.h
@@ -0,0 +1,151 @@
+/* -*- 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_config_gfxFeature_h
+#define mozilla_gfx_config_gfxFeature_h
+
+#include <functional>
+#include <stdint.h>
+#include "gfxTelemetry.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Maybe.h"
+#include "nsString.h"
+
+namespace mozilla {
+namespace gfx {
+
+#define GFX_FEATURE_MAP(_)                                           \
+  /* Name,                        Type,         Description */       \
+  _(HW_COMPOSITING, Feature, "Compositing")                          \
+  _(D3D11_COMPOSITING, Feature, "Direct3D11 Compositing")            \
+  _(OPENGL_COMPOSITING, Feature, "OpenGL Compositing")               \
+  _(DIRECT2D, Feature, "Direct2D")                                   \
+  _(D3D11_HW_ANGLE, Feature, "Direct3D11 hardware ANGLE")            \
+  _(DIRECT_DRAW, Feature, "DirectDraw")                              \
+  _(GPU_PROCESS, Feature, "GPU Process")                             \
+  _(WEBRENDER, Feature, "WebRender")                                 \
+  _(WEBRENDER_QUALIFIED, Feature, "WebRender qualified")             \
+  _(WEBRENDER_COMPOSITOR, Feature, "WebRender native compositor")    \
+  _(WEBRENDER_PARTIAL, Feature, "WebRender partial present")         \
+  _(WEBRENDER_ANGLE, Feature, "WebRender ANGLE")                     \
+  _(WEBRENDER_DCOMP_PRESENT, Feature, "WebRender DirectComposition") \
+  _(WEBRENDER_SOFTWARE, Feature, "WebRender software fallback")      \
+  _(OMTP, Feature, "Off Main Thread Painting")                       \
+  _(ADVANCED_LAYERS, Feature, "Advanced Layers")                     \
+  _(WEBGPU, Feature, "WebGPU")                                       \
+  /* Add new entries above this comment */
+
+enum class Feature : uint32_t {
+#define MAKE_ENUM(name, type, desc) name,
+  GFX_FEATURE_MAP(MAKE_ENUM)
+#undef MAKE_ENUM
+      NumValues
+};
+
+class FeatureState {
+  friend class gfxConfig;
+  friend class GfxConfigManager;  // for testing
+
+ public:
+  FeatureState() { Reset(); }
+
+  bool IsEnabled() const;
+  FeatureStatus GetValue() const;
+
+  void EnableByDefault();
+  void DisableByDefault(FeatureStatus aStatus, const char* aMessage,
+                        const nsACString& aFailureId);
+  bool SetDefault(bool aEnable, FeatureStatus aDisableStatus,
+                  const char* aDisableMessage);
+  bool InitOrUpdate(bool aEnable, FeatureStatus aDisableStatus,
+                    const char* aMessage);
+  void SetDefaultFromPref(const char* aPrefName, bool aIsEnablePref,
+                          bool aDefaultValue, Maybe<bool> aUserValue);
+  void SetDefaultFromPref(const char* aPrefName, bool aIsEnablePref,
+                          bool aDefaultValue);
+  void UserEnable(const char* aMessage);
+  void UserForceEnable(const char* aMessage);
+  void UserDisable(const char* aMessage, const nsACString& aFailureId);
+  void Disable(FeatureStatus aStatus, const char* aMessage,
+               const nsACString& aFailureId);
+  void ForceDisable(FeatureStatus aStatus, const char* aMessage,
+                    const nsACString& aFailureId) {
+    SetFailed(aStatus, aMessage, aFailureId);
+  }
+  void SetFailed(FeatureStatus aStatus, const char* aMessage,
+                 const nsACString& aFailureId);
+  bool MaybeSetFailed(bool aEnable, FeatureStatus aStatus, const char* aMessage,
+                      const nsACString& aFailureId);
+  bool MaybeSetFailed(FeatureStatus aStatus, const char* aMessage,
+                      const nsACString& aFailureId);
+
+  // aType is "base", "user", "env", or "runtime".
+  // aMessage may be null.
+  typedef std::function<void(const char* aType, FeatureStatus aStatus,
+                             const char* aMessage, const nsCString& aFailureId)>
+      StatusIterCallback;
+  void ForEachStatusChange(const StatusIterCallback& aCallback) const;
+
+  const char* GetFailureMessage() const;
+  const nsCString& GetFailureId() const;
+  nsCString GetStatusAndFailureIdString() const;
+
+  bool DisabledByDefault() const;
+
+ private:
+  void SetUser(FeatureStatus aStatus, const char* aMessage,
+               const nsACString& aFailureId);
+  void SetEnvironment(FeatureStatus aStatus, const char* aMessage,
+                      const nsACString& aFailureId);
+  void SetRuntime(FeatureStatus aStatus, const char* aMessage,
+                  const nsACString& aFailureId);
+  bool IsForcedOnByUser() const;
+  const char* GetRuntimeMessage() const;
+  bool IsInitialized() const { return mDefault.IsInitialized(); }
+
+  void AssertInitialized() const { MOZ_ASSERT(IsInitialized()); }
+
+  // Clear all state.
+  void Reset();
+
+ private:
+  struct Instance {
+    char mMessage[64];
+    FeatureStatus mStatus;
+    nsCString mFailureId;
+
+    void Set(FeatureStatus aStatus);
+    void Set(FeatureStatus aStatus, const char* aMessage,
+             const nsACString& aFailureId);
+    bool IsInitialized() const { return mStatus != FeatureStatus::Unused; }
+    const char* MessageOrNull() const {
+      return mMessage[0] != '\0' ? mMessage : nullptr;
+    }
+    const char* Message() const {
+      MOZ_ASSERT(MessageOrNull());
+      return mMessage;
+    }
+    const nsCString& FailureId() const { return mFailureId; }
+  };
+
+  // The default state is the state we decide on startup, based on the operating
+  // system or a base preference.
+  //
+  // The user state factors in any changes to preferences that the user made.
+  //
+  // The environment state factors in any additional decisions made, such as
+  // availability or blocklisting.
+  //
+  // The runtime state factors in any problems discovered at runtime.
+  Instance mDefault;
+  Instance mUser;
+  Instance mEnvironment;
+  Instance mRuntime;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_config_gfxFeature_h
diff --git a/gfx/config/gfxVarReceiver.h b/gfx/config/gfxVarReceiver.h
new file mode 100644
index 0000000000..ab026f2eb6
--- /dev/null
+++ b/gfx/config/gfxVarReceiver.h
@@ -0,0 +1,24 @@
+/* -*- 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_config_gfxVarReceiver_h
+#define mozilla_gfx_config_gfxVarReceiver_h
+
+namespace mozilla {
+namespace gfx {
+
+class GfxVarUpdate;
+
+// This allows downstream processes (such as PContent, PGPU) to listen for
+// updates on gfxVarReceiver.
+class gfxVarReceiver {
+ public:
+  virtual void OnVarChanged(const GfxVarUpdate& aVar) = 0;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_config_gfxVarReceiver_h
diff --git a/gfx/config/gfxVars.cpp b/gfx/config/gfxVars.cpp
new file mode 100644
index 0000000000..77a8470c3c
--- /dev/null
+++ b/gfx/config/gfxVars.cpp
@@ -0,0 +1,149 @@
+/* -*- 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 "gfxVars.h"
+#include "gfxVarReceiver.h"
+#include "mozilla/dom/ContentChild.h"
+
+namespace mozilla {
+namespace gfx {
+
+StaticAutoPtr<gfxVars> gfxVars::sInstance;
+StaticAutoPtr<nsTArray<gfxVars::VarBase*>> gfxVars::sVarList;
+
+StaticAutoPtr<nsTArray<GfxVarUpdate>> gGfxVarInitUpdates;
+
+void gfxVars::SetValuesForInitialize(
+    const nsTArray<GfxVarUpdate>& aInitUpdates) {
+  // This should only be called once
+  MOZ_RELEASE_ASSERT(!gGfxVarInitUpdates);
+
+  // We expect aInitUpdates to be provided before any other gfxVars operation,
+  // and for sInstance to be null here, but handle the alternative.
+  if (sInstance) {
+    // Apply the updates, the object has been created already
+    for (const auto& varUpdate : aInitUpdates) {
+      ApplyUpdate(varUpdate);
+    }
+  } else {
+    // Save the values for Initialize call
+    gGfxVarInitUpdates = new nsTArray<GfxVarUpdate>(aInitUpdates.Clone());
+  }
+}
+
+void gfxVars::Initialize() {
+  if (sInstance) {
+    MOZ_RELEASE_ASSERT(
+        !gGfxVarInitUpdates,
+        "Initial updates should not be present after any gfxVars operation");
+    return;
+  }
+
+  // sVarList must be initialized first since it's used in the constructor for
+  // sInstance.
+  sVarList = new nsTArray<gfxVars::VarBase*>();
+  sInstance = new gfxVars;
+
+  // Note the GPU process is not handled here - it cannot send sync
+  // messages, so instead the initial data is pushed down.
+  if (XRE_IsContentProcess()) {
+    MOZ_ASSERT(gGfxVarInitUpdates,
+               "Initial updates should be provided in content process");
+    if (!gGfxVarInitUpdates) {
+      // No provided initial updates, sync-request them from parent.
+      nsTArray<GfxVarUpdate> initUpdates;
+      dom::ContentChild::GetSingleton()->SendGetGfxVars(&initUpdates);
+      gGfxVarInitUpdates = new nsTArray<GfxVarUpdate>(std::move(initUpdates));
+    }
+    for (const auto& varUpdate : *gGfxVarInitUpdates) {
+      ApplyUpdate(varUpdate);
+    }
+    gGfxVarInitUpdates = nullptr;
+  }
+}
+
+gfxVars::gfxVars() = default;
+
+void gfxVars::Shutdown() {
+  sInstance = nullptr;
+  sVarList = nullptr;
+  gGfxVarInitUpdates = nullptr;
+}
+
+/* static */
+void gfxVars::ApplyUpdate(const GfxVarUpdate& aUpdate) {
+  // Only subprocesses receive updates and apply them locally.
+  MOZ_ASSERT(!XRE_IsParentProcess());
+  MOZ_DIAGNOSTIC_ASSERT(sVarList || gGfxVarInitUpdates);
+  if (sVarList) {
+    sVarList->ElementAt(aUpdate.index())->SetValue(aUpdate.value());
+  } else if (gGfxVarInitUpdates) {
+    // Too early, we haven't been initialized, so just add to
+    // the array waiting for the initialization...
+    gGfxVarInitUpdates->AppendElement(aUpdate);
+  }
+}
+
+/* static */
+void gfxVars::AddReceiver(gfxVarReceiver* aReceiver) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Don't double-add receivers, in case a broken content process sends two
+  // init messages.
+  if (!sInstance->mReceivers.Contains(aReceiver)) {
+    sInstance->mReceivers.AppendElement(aReceiver);
+  }
+}
+
+/* static */
+void gfxVars::RemoveReceiver(gfxVarReceiver* aReceiver) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (sInstance) {
+    sInstance->mReceivers.RemoveElement(aReceiver);
+  }
+}
+
+/* static */
+nsTArray<GfxVarUpdate> gfxVars::FetchNonDefaultVars() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sVarList);
+
+  nsTArray<GfxVarUpdate> updates;
+  for (size_t i = 0; i < sVarList->Length(); i++) {
+    VarBase* var = sVarList->ElementAt(i);
+    if (var->HasDefaultValue()) {
+      continue;
+    }
+
+    GfxVarValue value;
+    var->GetValue(&value);
+
+    updates.AppendElement(GfxVarUpdate(i, value));
+  }
+
+  return updates;
+}
+
+gfxVars::VarBase::VarBase() {
+  mIndex = gfxVars::sVarList->Length();
+  gfxVars::sVarList->AppendElement(this);
+}
+
+void gfxVars::NotifyReceivers(VarBase* aVar) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  GfxVarValue value;
+  aVar->GetValue(&value);
+
+  GfxVarUpdate update(aVar->Index(), value);
+  for (auto& receiver : mReceivers) {
+    receiver->OnVarChanged(update);
+  }
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/config/gfxVars.h b/gfx/config/gfxVars.h
new file mode 100644
index 0000000000..694bbeb763
--- /dev/null
+++ b/gfx/config/gfxVars.h
@@ -0,0 +1,209 @@
+/* -*- 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_config_gfxVars_h
+#define mozilla_gfx_config_gfxVars_h
+
+#include <stdint.h>
+#include "mozilla/Assertions.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/gfx/GraphicsMessages.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/Types.h"
+#include "nsTArray.h"
+#include "nsXULAppAPI.h"
+
+namespace mozilla {
+namespace gfx {
+
+class gfxVarReceiver;
+
+// Generator for graphics vars.
+#define GFX_VARS_LIST(_)                                           \
+  /* C++ Name,                  Data Type,        Default Value */ \
+  _(AllowEglRbab, bool, true)                                      \
+  _(AllowWebgl2, bool, true)                                       \
+  _(AllowWebglAccelAngle, bool, true)                              \
+  _(AllowWebglOop, bool, true)                                     \
+  _(BrowserTabsRemoteAutostart, bool, false)                       \
+  _(ContentBackend, BackendType, BackendType::NONE)                \
+  _(SoftwareBackend, BackendType, BackendType::NONE)               \
+  _(TileSize, IntSize, IntSize(-1, -1))                            \
+  _(UseXRender, bool, false)                                       \
+  _(OffscreenFormat, gfxImageFormat,                               \
+    mozilla::gfx::SurfaceFormat::X8R8G8B8_UINT32)                  \
+  _(RequiresAcceleratedGLContextForCompositorOGL, bool, false)     \
+  _(CanUseHardwareVideoDecoding, bool, false)                      \
+  _(DXInterop2Blocked, bool, false)                                \
+  _(DXNV12Blocked, bool, false)                                    \
+  _(DXP010Blocked, bool, false)                                    \
+  _(DXP016Blocked, bool, false)                                    \
+  _(UseWebRender, bool, false)                                     \
+  _(UseWebRenderANGLE, bool, false)                                \
+  _(UseWebRenderFlipSequentialWin, bool, false)                    \
+  _(UseWebRenderDCompWin, bool, false)                             \
+  _(UseWebRenderDCompVideoOverlayWin, bool, false)                 \
+  _(UseWebRenderTripleBufferingWin, bool, false)                   \
+  _(UseWebRenderCompositor, bool, false)                           \
+  _(UseWebRenderProgramBinaryDisk, bool, false)                    \
+  _(UseWebRenderOptimizedShaders, bool, false)                     \
+  _(UseWebRenderMultithreading, bool, false)                       \
+  _(UseWebRenderScissoredCacheClears, bool, true)                  \
+  _(WebRenderProfilerUI, nsCString, nsCString())                   \
+  _(WebglAllowCoreProfile, bool, true)                             \
+  _(WebglAllowWindowsNativeGl, bool, false)                        \
+  _(WebRenderMaxPartialPresentRects, int32_t, 0)                   \
+  _(WebRenderDebugFlags, int32_t, 0)                               \
+  _(WebRenderBatchingLookback, int32_t, 10)                        \
+  _(UseSoftwareWebRender, bool, false)                             \
+  _(ScreenDepth, int32_t, 0)                                       \
+  _(GREDirectory, nsString, nsString())                            \
+  _(ProfDirectory, nsString, nsString())                           \
+  _(UseOMTP, bool, false)                                          \
+  _(AllowD3D11KeyedMutex, bool, false)                             \
+  _(SystemTextQuality, int32_t, 5 /* CLEARTYPE_QUALITY */)         \
+  _(LayersWindowRecordingPath, nsCString, nsCString())             \
+  _(RemoteCanvasEnabled, bool, false)                              \
+  _(UseDoubleBufferingWithCompositor, bool, false)                 \
+  _(UseGLSwizzle, bool, true)                                      \
+  _(ForceSubpixelAAWherePossible, bool, false)                     \
+  _(DwmCompositionEnabled, bool, true)                             \
+  _(FxREmbedded, bool, false)                                      \
+  _(UseAHardwareBufferContent, bool, false)                        \
+  _(UseAHardwareBufferSharedSurface, bool, false)                  \
+  _(UseEGL, bool, false)                                           \
+  _(DrmRenderDevice, nsCString, nsCString())
+
+/* Add new entries above this line. */
+
+// Some graphics settings are computed on the UI process and must be
+// communicated to content and GPU processes. gfxVars helps facilitate
+// this. Its function is similar to StaticPrefs, except rather than hold
+// user preferences, it holds dynamically computed values.
+//
+// Each variable in GFX_VARS_LIST exposes the following static methods:
+//
+//    const DataType& CxxName();
+//    void SetCxxName(const DataType& aValue);
+//
+// Note that the setter may only be called in the UI process; a gfxVar must be
+// a variable that is determined in the UI process and pushed to child
+// processes.
+class gfxVars final {
+ public:
+  // These values will be used during the Initialize() call if set.  Any
+  // updates that come before initialization will get added to this array.
+  static void SetValuesForInitialize(
+      const nsTArray<GfxVarUpdate>& aInitUpdates);
+
+  static void Initialize();
+  static void Shutdown();
+
+  static void ApplyUpdate(const GfxVarUpdate& aUpdate);
+  static void AddReceiver(gfxVarReceiver* aReceiver);
+  static void RemoveReceiver(gfxVarReceiver* aReceiver);
+
+  // Return a list of updates for all variables with non-default values.
+  static nsTArray<GfxVarUpdate> FetchNonDefaultVars();
+
+ public:
+  // Each variable must expose Set and Get methods for IPDL.
+  class VarBase {
+   public:
+    VarBase();
+    virtual void SetValue(const GfxVarValue& aValue) = 0;
+    virtual void GetValue(GfxVarValue* aOutValue) = 0;
+    virtual bool HasDefaultValue() const = 0;
+    size_t Index() const { return mIndex; }
+
+   private:
+    size_t mIndex;
+  };
+
+ private:
+  static StaticAutoPtr<gfxVars> sInstance;
+  static StaticAutoPtr<nsTArray<VarBase*>> sVarList;
+
+  template <typename T, T Default(), T GetFrom(const GfxVarValue& aValue)>
+  class VarImpl final : public VarBase {
+   public:
+    VarImpl() : mValue(Default()) {}
+    void SetValue(const GfxVarValue& aValue) override {
+      mValue = GetFrom(aValue);
+      if (mListener) {
+        mListener();
+      }
+    }
+    void GetValue(GfxVarValue* aOutValue) override {
+      *aOutValue = GfxVarValue(mValue);
+    }
+    bool HasDefaultValue() const override { return mValue == Default(); }
+    const T& Get() const { return mValue; }
+    // Return true if the value changed, false otherwise.
+    bool Set(const T& aValue) {
+      MOZ_ASSERT(XRE_IsParentProcess());
+      if (mValue == aValue) {
+        return false;
+      }
+      mValue = aValue;
+      if (mListener) {
+        mListener();
+      }
+      return true;
+    }
+
+    void SetListener(const std::function<void()>& aListener) {
+      mListener = aListener;
+    }
+
+   private:
+    T mValue;
+    std::function<void()> mListener;
+  };
+
+#define GFX_VAR_DECL(CxxName, DataType, DefaultValue)                          \
+ private:                                                                      \
+  static DataType Get##CxxName##Default() { return DefaultValue; }             \
+  static DataType Get##CxxName##From(const GfxVarValue& aValue) {              \
+    return aValue.get_##DataType();                                            \
+  }                                                                            \
+  VarImpl<DataType, Get##CxxName##Default, Get##CxxName##From> mVar##CxxName;  \
+                                                                               \
+ public:                                                                       \
+  static const DataType& CxxName() { return sInstance->mVar##CxxName.Get(); }  \
+  static DataType Get##CxxName##OrDefault() {                                  \
+    if (!sInstance) {                                                          \
+      return DefaultValue;                                                     \
+    }                                                                          \
+    return sInstance->mVar##CxxName.Get();                                     \
+  }                                                                            \
+  static void Set##CxxName(const DataType& aValue) {                           \
+    if (sInstance->mVar##CxxName.Set(aValue)) {                                \
+      sInstance->NotifyReceivers(&sInstance->mVar##CxxName);                   \
+    }                                                                          \
+  }                                                                            \
+                                                                               \
+  static void Set##CxxName##Listener(const std::function<void()>& aListener) { \
+    sInstance->mVar##CxxName.SetListener(aListener);                           \
+  }
+
+  GFX_VARS_LIST(GFX_VAR_DECL)
+#undef GFX_VAR_DECL
+
+ private:
+  gfxVars();
+
+  void NotifyReceivers(VarBase* aVar);
+
+ private:
+  nsTArray<gfxVarReceiver*> mReceivers;
+};
+
+#undef GFX_VARS_LIST
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_config_gfxVars_h
diff --git a/gfx/config/moz.build b/gfx/config/moz.build
new file mode 100644
index 0000000000..a19b39a592
--- /dev/null
+++ b/gfx/config/moz.build
@@ -0,0 +1,28 @@
+# -*- 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/.
+
+EXPORTS += [
+    "gfxConfig.h",
+    "gfxFallback.h",
+    "gfxFeature.h",
+]
+
+EXPORTS.mozilla.gfx += [
+    "gfxConfigManager.h",
+    "gfxVarReceiver.h",
+    "gfxVars.h",
+]
+
+UNIFIED_SOURCES += [
+    "gfxConfig.cpp",
+    "gfxConfigManager.cpp",
+    "gfxFeature.cpp",
+    "gfxVars.cpp",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"