Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

43 files changed, 8107 insertions, 0 deletions

diff --git a/gfx/ipc/CanvasManagerChild.cpp b/gfx/ipc/CanvasManagerChild.cpp
new file mode 100644
index 0000000000..29f496ab24
--- /dev/null
+++ b/gfx/ipc/CanvasManagerChild.cpp
@@ -0,0 +1,229 @@
+/* -*- 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 "CanvasManagerChild.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Swizzle.h"
+#include "mozilla/ipc/Endpoint.h"
+#include "mozilla/layers/CompositorManagerChild.h"
+#include "mozilla/webgpu/WebGPUChild.h"
+
+using namespace mozilla::dom;
+using namespace mozilla::layers;
+
+namespace mozilla::gfx {
+
+// The IPDL actor holds a strong reference to CanvasManagerChild which we use
+// to keep it alive. The owning thread will tell us to close when it is
+// shutdown, either via CanvasManagerChild::Shutdown for the main thread, or
+// via a shutdown callback from IPCWorkerRef for worker threads.
+MOZ_THREAD_LOCAL(CanvasManagerChild*) CanvasManagerChild::sLocalManager;
+
+Atomic<uint32_t> CanvasManagerChild::sNextId(1);
+
+CanvasManagerChild::CanvasManagerChild(uint32_t aId) : mId(aId) {}
+CanvasManagerChild::~CanvasManagerChild() = default;
+
+void CanvasManagerChild::ActorDestroy(ActorDestroyReason aReason) {
+  if (sLocalManager.get() == this) {
+    sLocalManager.set(nullptr);
+  }
+}
+
+void CanvasManagerChild::Destroy() {
+  // The caller has a strong reference. ActorDestroy will clear sLocalManager.
+  Close();
+  mWorkerRef = nullptr;
+}
+
+/* static */ void CanvasManagerChild::Shutdown() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // The worker threads should destroy their own CanvasManagerChild instances
+  // during their shutdown sequence. We just need to take care of the main
+  // thread. We need to init here because we may have never created a
+  // CanvasManagerChild for the main thread in the first place.
+  if (sLocalManager.init()) {
+    RefPtr<CanvasManagerChild> manager = sLocalManager.get();
+    if (manager) {
+      manager->Destroy();
+    }
+  }
+}
+
+/* static */ bool CanvasManagerChild::CreateParent(
+    ipc::Endpoint<PCanvasManagerParent>&& aEndpoint) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  CompositorManagerChild* manager = CompositorManagerChild::GetInstance();
+  if (!manager || !manager->CanSend()) {
+    return false;
+  }
+
+  return manager->SendInitCanvasManager(std::move(aEndpoint));
+}
+
+/* static */ CanvasManagerChild* CanvasManagerChild::Get() {
+  if (NS_WARN_IF(!sLocalManager.init())) {
+    return nullptr;
+  }
+
+  CanvasManagerChild* managerWeak = sLocalManager.get();
+  if (managerWeak) {
+    return managerWeak;
+  }
+
+  // We are only used on the main thread, or on worker threads.
+  WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
+  MOZ_ASSERT_IF(!worker, NS_IsMainThread());
+
+  ipc::Endpoint<PCanvasManagerParent> parentEndpoint;
+  ipc::Endpoint<PCanvasManagerChild> childEndpoint;
+
+  auto compositorPid = CompositorManagerChild::GetOtherPid();
+  if (NS_WARN_IF(!compositorPid)) {
+    return nullptr;
+  }
+
+  nsresult rv = PCanvasManager::CreateEndpoints(
+      compositorPid, base::GetCurrentProcId(), &parentEndpoint, &childEndpoint);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nullptr;
+  }
+
+  auto manager = MakeRefPtr<CanvasManagerChild>(sNextId++);
+
+  if (worker) {
+    // The IPCWorkerRef will let us know when the worker is shutting down. This
+    // will let us clear our threadlocal reference and close the actor. We rely
+    // upon an explicit shutdown for the main thread.
+    manager->mWorkerRef = IPCWorkerRef::Create(
+        worker, "CanvasManager", [manager]() { manager->Destroy(); });
+    if (NS_WARN_IF(!manager->mWorkerRef)) {
+      return nullptr;
+    }
+  }
+
+  if (NS_WARN_IF(!childEndpoint.Bind(manager))) {
+    return nullptr;
+  }
+
+  // We can't talk to the compositor process directly from worker threads, but
+  // the main thread can via CompositorManagerChild.
+  if (worker) {
+    worker->DispatchToMainThread(NS_NewRunnableFunction(
+        "CanvasManagerChild::CreateParent",
+        [parentEndpoint = std::move(parentEndpoint)]() {
+          CreateParent(
+              std::move(const_cast<ipc::Endpoint<PCanvasManagerParent>&&>(
+                  parentEndpoint)));
+        }));
+  } else if (NS_WARN_IF(!CreateParent(std::move(parentEndpoint)))) {
+    return nullptr;
+  }
+
+  manager->SendInitialize(manager->Id());
+  sLocalManager.set(manager);
+  return manager;
+}
+
+RefPtr<webgpu::WebGPUChild> CanvasManagerChild::GetWebGPUChild() {
+  if (!mWebGPUChild) {
+    mWebGPUChild = MakeAndAddRef<webgpu::WebGPUChild>();
+    if (!SendPWebGPUConstructor(mWebGPUChild)) {
+      mWebGPUChild = nullptr;
+    }
+  }
+
+  return mWebGPUChild;
+}
+
+already_AddRefed<DataSourceSurface> CanvasManagerChild::GetSnapshot(
+    uint32_t aManagerId, int32_t aProtocolId,
+    const Maybe<RemoteTextureOwnerId>& aOwnerId, SurfaceFormat aFormat,
+    bool aPremultiply, bool aYFlip) {
+  if (!CanSend()) {
+    return nullptr;
+  }
+
+  webgl::FrontBufferSnapshotIpc res;
+  if (!SendGetSnapshot(aManagerId, aProtocolId, aOwnerId, &res)) {
+    return nullptr;
+  }
+
+  if (!res.shmem || !res.shmem->IsReadable()) {
+    return nullptr;
+  }
+
+  auto guard = MakeScopeExit([&] { DeallocShmem(res.shmem.ref()); });
+
+  if (!res.surfSize.x || !res.surfSize.y || res.surfSize.x > INT32_MAX ||
+      res.surfSize.y > INT32_MAX) {
+    return nullptr;
+  }
+
+  IntSize size(res.surfSize.x, res.surfSize.y);
+  CheckedInt32 stride = CheckedInt32(size.width) * sizeof(uint32_t);
+  if (!stride.isValid()) {
+    return nullptr;
+  }
+
+  CheckedInt32 length = stride * size.height;
+  if (!length.isValid() ||
+      size_t(length.value()) != res.shmem->Size<uint8_t>()) {
+    return nullptr;
+  }
+
+  SurfaceFormat format =
+      IsOpaque(aFormat) ? SurfaceFormat::B8G8R8X8 : SurfaceFormat::B8G8R8A8;
+  RefPtr<DataSourceSurface> surface =
+      Factory::CreateDataSourceSurfaceWithStride(size, format, stride.value(),
+                                                 /* aZero */ false);
+  if (!surface) {
+    return nullptr;
+  }
+
+  gfx::DataSourceSurface::ScopedMap map(surface,
+                                        gfx::DataSourceSurface::READ_WRITE);
+  if (!map.IsMapped()) {
+    return nullptr;
+  }
+
+  // The buffer we may readback from the canvas could be R8G8B8A8, not
+  // premultiplied, and/or has its rows iverted. For the general case, we want
+  // surfaces represented as premultiplied B8G8R8A8, with its rows ordered top
+  // to bottom. Given this path is used for screenshots/SurfaceFromElement,
+  // that's the representation we need.
+  if (aYFlip) {
+    if (aPremultiply) {
+      if (!PremultiplyYFlipData(res.shmem->get<uint8_t>(), stride.value(),
+                                aFormat, map.GetData(), map.GetStride(), format,
+                                size)) {
+        return nullptr;
+      }
+    } else {
+      if (!SwizzleYFlipData(res.shmem->get<uint8_t>(), stride.value(), aFormat,
+                            map.GetData(), map.GetStride(), format, size)) {
+        return nullptr;
+      }
+    }
+  } else if (aPremultiply) {
+    if (!PremultiplyData(res.shmem->get<uint8_t>(), stride.value(), aFormat,
+                         map.GetData(), map.GetStride(), format, size)) {
+      return nullptr;
+    }
+  } else {
+    if (!SwizzleData(res.shmem->get<uint8_t>(), stride.value(), aFormat,
+                     map.GetData(), map.GetStride(), format, size)) {
+      return nullptr;
+    }
+  }
+  return surface.forget();
+}
+
+}  // namespace mozilla::gfx
diff --git a/gfx/ipc/CanvasManagerChild.h b/gfx/ipc/CanvasManagerChild.h
new file mode 100644
index 0000000000..bf5c774159
--- /dev/null
+++ b/gfx/ipc/CanvasManagerChild.h
@@ -0,0 +1,61 @@
+/* -*- 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 _include_gfx_ipc_CanvasManagerChild_h__
+#define _include_gfx_ipc_CanvasManagerChild_h__
+
+#include "mozilla/Atomics.h"
+#include "mozilla/gfx/PCanvasManagerChild.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/ThreadLocal.h"
+
+namespace mozilla {
+namespace dom {
+class IPCWorkerRef;
+class WorkerPrivate;
+}  // namespace dom
+
+namespace webgpu {
+class WebGPUChild;
+}  // namespace webgpu
+
+namespace gfx {
+class DataSourceSurface;
+
+class CanvasManagerChild final : public PCanvasManagerChild {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CanvasManagerChild, override);
+
+  explicit CanvasManagerChild(uint32_t aId);
+  uint32_t Id() const { return mId; }
+  already_AddRefed<DataSourceSurface> GetSnapshot(
+      uint32_t aManagerId, int32_t aProtocolId,
+      const Maybe<RemoteTextureOwnerId>& aOwnerId, SurfaceFormat aFormat,
+      bool aPremultiply, bool aYFlip);
+  void ActorDestroy(ActorDestroyReason aReason) override;
+
+  static CanvasManagerChild* Get();
+  static void Shutdown();
+  static bool CreateParent(
+      mozilla::ipc::Endpoint<PCanvasManagerParent>&& aEndpoint);
+
+  RefPtr<webgpu::WebGPUChild> GetWebGPUChild();
+
+ private:
+  ~CanvasManagerChild();
+  void Destroy();
+
+  RefPtr<mozilla::dom::IPCWorkerRef> mWorkerRef;
+  RefPtr<webgpu::WebGPUChild> mWebGPUChild;
+  const uint32_t mId;
+
+  static MOZ_THREAD_LOCAL(CanvasManagerChild*) sLocalManager;
+  static Atomic<uint32_t> sNextId;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_gfx_ipc_CanvasManagerChild_h__
diff --git a/gfx/ipc/CanvasManagerParent.cpp b/gfx/ipc/CanvasManagerParent.cpp
new file mode 100644
index 0000000000..a697bf8444
--- /dev/null
+++ b/gfx/ipc/CanvasManagerParent.cpp
@@ -0,0 +1,188 @@
+/* -*- 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 "CanvasManagerParent.h"
+#include "mozilla/dom/WebGLParent.h"
+#include "mozilla/gfx/CanvasRenderThread.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/ipc/Endpoint.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/StaticPrefs_webgl.h"
+#include "mozilla/webgpu/WebGPUParent.h"
+#include "mozilla/webrender/RenderThread.h"
+#include "nsIThread.h"
+#include "nsThreadUtils.h"
+
+namespace mozilla::gfx {
+
+CanvasManagerParent::ManagerSet CanvasManagerParent::sManagers;
+
+/* static */ void CanvasManagerParent::Init(
+    Endpoint<PCanvasManagerParent>&& aEndpoint) {
+  MOZ_ASSERT(layers::CompositorThreadHolder::IsInCompositorThread());
+
+  auto manager = MakeRefPtr<CanvasManagerParent>();
+
+  if (!gfxVars::SupportsThreadsafeGL()) {
+    nsCOMPtr<nsIThread> owningThread;
+    owningThread = wr::RenderThread::GetRenderThread();
+    MOZ_ASSERT(owningThread);
+
+    owningThread->Dispatch(NewRunnableMethod<Endpoint<PCanvasManagerParent>&&>(
+        "CanvasManagerParent::Bind", manager, &CanvasManagerParent::Bind,
+        std::move(aEndpoint)));
+  } else if (gfxVars::UseCanvasRenderThread()) {
+    nsCOMPtr<nsIThread> owningThread;
+    owningThread = gfx::CanvasRenderThread::GetCanvasRenderThread();
+    MOZ_ASSERT(owningThread);
+
+    owningThread->Dispatch(NewRunnableMethod<Endpoint<PCanvasManagerParent>&&>(
+        "CanvasManagerParent::Bind", manager, &CanvasManagerParent::Bind,
+        std::move(aEndpoint)));
+  } else {
+    manager->Bind(std::move(aEndpoint));
+  }
+}
+
+/* static */ void CanvasManagerParent::Shutdown() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsISerialEventTarget> owningThread;
+  if (!gfxVars::SupportsThreadsafeGL()) {
+    owningThread = wr::RenderThread::GetRenderThread();
+  } else if (gfxVars::UseCanvasRenderThread()) {
+    owningThread = gfx::CanvasRenderThread::GetCanvasRenderThread();
+  } else {
+    owningThread = layers::CompositorThread();
+  }
+  if (!owningThread) {
+    return;
+  }
+
+  NS_DispatchAndSpinEventLoopUntilComplete(
+      "CanvasManagerParent::Shutdown"_ns, owningThread,
+      NS_NewRunnableFunction("CanvasManagerParent::Shutdown", []() -> void {
+        CanvasManagerParent::ShutdownInternal();
+      }));
+}
+
+/* static */ void CanvasManagerParent::ShutdownInternal() {
+  nsTArray<RefPtr<CanvasManagerParent>> actors(sManagers.Count());
+  // Do a copy since Close will remove the entry from the set.
+  for (const auto& actor : sManagers) {
+    actors.AppendElement(actor);
+  }
+
+  for (auto const& actor : actors) {
+    actor->Close();
+  }
+}
+
+CanvasManagerParent::CanvasManagerParent() = default;
+CanvasManagerParent::~CanvasManagerParent() = default;
+
+void CanvasManagerParent::Bind(Endpoint<PCanvasManagerParent>&& aEndpoint) {
+  if (!aEndpoint.Bind(this)) {
+    NS_WARNING("Failed to bind CanvasManagerParent!");
+    return;
+  }
+
+  sManagers.Insert(this);
+}
+
+void CanvasManagerParent::ActorDestroy(ActorDestroyReason aWhy) {
+  sManagers.Remove(this);
+}
+
+already_AddRefed<dom::PWebGLParent> CanvasManagerParent::AllocPWebGLParent() {
+  if (NS_WARN_IF(!gfxVars::AllowWebglOop() &&
+                 !StaticPrefs::webgl_out_of_process_force())) {
+    MOZ_ASSERT_UNREACHABLE("AllocPWebGLParent without remote WebGL");
+    return nullptr;
+  }
+  return MakeAndAddRef<dom::WebGLParent>();
+}
+
+already_AddRefed<webgpu::PWebGPUParent>
+CanvasManagerParent::AllocPWebGPUParent() {
+  if (NS_WARN_IF(!gfxVars::AllowWebGPU())) {
+    MOZ_ASSERT_UNREACHABLE("AllocPWebGPUParent without WebGPU");
+    return nullptr;
+  }
+
+  return MakeAndAddRef<webgpu::WebGPUParent>();
+}
+
+mozilla::ipc::IPCResult CanvasManagerParent::RecvInitialize(
+    const uint32_t& aId) {
+  if (!aId) {
+    return IPC_FAIL(this, "invalid id");
+  }
+  if (mId) {
+    return IPC_FAIL(this, "already initialized");
+  }
+  mId = aId;
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CanvasManagerParent::RecvGetSnapshot(
+    const uint32_t& aManagerId, const int32_t& aProtocolId,
+    const Maybe<RemoteTextureOwnerId>& aOwnerId,
+    webgl::FrontBufferSnapshotIpc* aResult) {
+  if (!aManagerId) {
+    return IPC_FAIL(this, "invalid id");
+  }
+
+  IProtocol* actor = nullptr;
+  for (CanvasManagerParent* i : sManagers) {
+    if (i->OtherPidMaybeInvalid() == OtherPidMaybeInvalid() &&
+        i->mId == aManagerId) {
+      actor = i->Lookup(aProtocolId);
+      break;
+    }
+  }
+
+  if (!actor) {
+    return IPC_FAIL(this, "invalid actor");
+  }
+
+  if (actor->GetSide() != mozilla::ipc::Side::ParentSide) {
+    return IPC_FAIL(this, "unsupported actor");
+  }
+
+  webgl::FrontBufferSnapshotIpc buffer;
+  switch (actor->GetProtocolId()) {
+    case ProtocolId::PWebGLMsgStart: {
+      RefPtr<dom::WebGLParent> webgl = static_cast<dom::WebGLParent*>(actor);
+      mozilla::ipc::IPCResult rv = webgl->GetFrontBufferSnapshot(&buffer, this);
+      if (!rv) {
+        return rv;
+      }
+    } break;
+    case ProtocolId::PWebGPUMsgStart: {
+      RefPtr<webgpu::WebGPUParent> webgpu =
+          static_cast<webgpu::WebGPUParent*>(actor);
+      IntSize size;
+      if (aOwnerId.isNothing()) {
+        return IPC_FAIL(this, "invalid OwnerId");
+      }
+      mozilla::ipc::IPCResult rv =
+          webgpu->GetFrontBufferSnapshot(this, *aOwnerId, buffer.shmem, size);
+      if (!rv) {
+        return rv;
+      }
+      buffer.surfSize.x = static_cast<uint32_t>(size.width);
+      buffer.surfSize.y = static_cast<uint32_t>(size.height);
+    } break;
+    default:
+      return IPC_FAIL(this, "unsupported protocol");
+  }
+
+  *aResult = std::move(buffer);
+  return IPC_OK();
+}
+
+}  // namespace mozilla::gfx
diff --git a/gfx/ipc/CanvasManagerParent.h b/gfx/ipc/CanvasManagerParent.h
new file mode 100644
index 0000000000..e74d64cc4a
--- /dev/null
+++ b/gfx/ipc/CanvasManagerParent.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 _include_gfx_ipc_CanvasManagerParent_h__
+#define _include_gfx_ipc_CanvasManagerParent_h__
+
+#include "mozilla/gfx/PCanvasManagerParent.h"
+#include "nsHashtablesFwd.h"
+
+namespace mozilla::gfx {
+
+class CanvasManagerParent final : public PCanvasManagerParent {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CanvasManagerParent, override);
+
+  static void Init(Endpoint<PCanvasManagerParent>&& aEndpoint);
+
+  static void Shutdown();
+
+  CanvasManagerParent();
+
+  void Bind(Endpoint<PCanvasManagerParent>&& aEndpoint);
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+
+  already_AddRefed<PWebGLParent> AllocPWebGLParent();
+  already_AddRefed<PWebGPUParent> AllocPWebGPUParent();
+
+  mozilla::ipc::IPCResult RecvInitialize(const uint32_t& aId);
+  mozilla::ipc::IPCResult RecvGetSnapshot(
+      const uint32_t& aManagerId, const int32_t& aProtocolId,
+      const Maybe<RemoteTextureOwnerId>& aOwnerId,
+      webgl::FrontBufferSnapshotIpc* aResult);
+
+ private:
+  static void ShutdownInternal();
+
+  ~CanvasManagerParent() override;
+
+  uint32_t mId = 0;
+
+  using ManagerSet = nsTHashSet<CanvasManagerParent*>;
+  static ManagerSet sManagers;
+};
+
+}  // namespace mozilla::gfx
+
+#endif  // _include_gfx_ipc_CanvasManagerParent_h__
diff --git a/gfx/ipc/CanvasRenderThread.cpp b/gfx/ipc/CanvasRenderThread.cpp
new file mode 100644
index 0000000000..5af627d8eb
--- /dev/null
+++ b/gfx/ipc/CanvasRenderThread.cpp
@@ -0,0 +1,120 @@
+/* -*- 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 "CanvasRenderThread.h"
+
+#include "mozilla/BackgroundHangMonitor.h"
+#include "transport/runnable_utils.h"
+
+namespace mozilla::gfx {
+
+static StaticRefPtr<CanvasRenderThread> sCanvasRenderThread;
+static mozilla::BackgroundHangMonitor* sBackgroundHangMonitor;
+#ifdef DEBUG
+static bool sCanvasRenderThreadEverStarted = false;
+#endif
+
+CanvasRenderThread::CanvasRenderThread(RefPtr<nsIThread> aThread)
+    : mThread(std::move(aThread)) {}
+
+CanvasRenderThread::~CanvasRenderThread() {}
+
+// static
+CanvasRenderThread* CanvasRenderThread::Get() { return sCanvasRenderThread; }
+
+// static
+void CanvasRenderThread::Start() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!sCanvasRenderThread);
+
+#ifdef DEBUG
+  // Check to ensure nobody will try to ever start us more than once during
+  // the process' lifetime (in particular after Stop).
+  MOZ_ASSERT(!sCanvasRenderThreadEverStarted);
+  sCanvasRenderThreadEverStarted = true;
+#endif
+
+  // This is 4M, which is higher than the default 256K.
+  // Increased with bug 1753349 to accommodate the `chromium/5359` branch of
+  // ANGLE, which has large peak stack usage for some pathological shader
+  // compilations.
+  //
+  // Previously increased to 512K to accommodate Mesa in bug 1753340.
+  //
+  // Previously increased to 320K to avoid a stack overflow in the
+  // Intel Vulkan driver initialization in bug 1716120.
+  //
+  // Note: we only override it if it's limited already.
+  const uint32_t stackSize =
+      nsIThreadManager::DEFAULT_STACK_SIZE ? 4096 << 10 : 0;
+
+  RefPtr<nsIThread> thread;
+  nsresult rv = NS_NewNamedThread(
+      "CanvasRenderer", getter_AddRefs(thread),
+      NS_NewRunnableFunction(
+          "CanvasRender::BackgroundHangSetup",
+          []() {
+            sBackgroundHangMonitor = new mozilla::BackgroundHangMonitor(
+                "CanvasRendererBHM",
+                /* Timeout values are powers-of-two to enable us get better
+                   data. 128ms is chosen for transient hangs because 8Hz should
+                   be the minimally acceptable goal for Compositor
+                   responsiveness (normal goal is 60Hz). */
+                128,
+                /* 2048ms is chosen for permanent hangs because it's longer than
+                 * most Compositor hangs seen in the wild, but is short enough
+                 * to not miss getting native hang stacks. */
+                2048);
+            nsCOMPtr<nsIThread> thread = NS_GetCurrentThread();
+            nsThread* nsthread = static_cast<nsThread*>(thread.get());
+            nsthread->SetUseHangMonitor(true);
+            nsthread->SetPriority(nsISupportsPriority::PRIORITY_HIGH);
+          }),
+      {.stackSize = stackSize});
+
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  sCanvasRenderThread = new CanvasRenderThread(thread);
+}
+
+// static
+void CanvasRenderThread::ShutDown() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sCanvasRenderThread);
+
+  // Null out sCanvasRenderThread before we enter synchronous Shutdown,
+  // from here on we are to be considered shut down for our consumers.
+  nsCOMPtr<nsIThread> oldThread = sCanvasRenderThread->GetCanvasRenderThread();
+  sCanvasRenderThread = nullptr;
+
+  // We do a synchronous shutdown here while spinning the MT event loop.
+  MOZ_ASSERT(oldThread);
+  oldThread->Shutdown();
+}
+
+// static
+bool CanvasRenderThread::IsInCanvasRenderThread() {
+  return sCanvasRenderThread &&
+         sCanvasRenderThread->mThread == NS_GetCurrentThread();
+}
+
+// static
+already_AddRefed<nsIThread> CanvasRenderThread::GetCanvasRenderThread() {
+  nsCOMPtr<nsIThread> thread;
+  if (sCanvasRenderThread) {
+    thread = sCanvasRenderThread->mThread;
+  }
+  return thread.forget();
+}
+
+void CanvasRenderThread::PostRunnable(already_AddRefed<nsIRunnable> aRunnable) {
+  nsCOMPtr<nsIRunnable> runnable = aRunnable;
+  mThread->Dispatch(runnable.forget());
+}
+
+}  // namespace mozilla::gfx
diff --git a/gfx/ipc/CanvasRenderThread.h b/gfx/ipc/CanvasRenderThread.h
new file mode 100644
index 0000000000..08dd6c6d54
--- /dev/null
+++ b/gfx/ipc/CanvasRenderThread.h
@@ -0,0 +1,50 @@
+/* -*- 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 _include_gfx_ipc_CanvasRenderThread_h__
+#define _include_gfx_ipc_CanvasRenderThread_h__
+
+#include "mozilla/DataMutex.h"
+#include "mozilla/layers/SynchronousTask.h"
+#include "mozilla/StaticPtr.h"
+#include "nsISupportsImpl.h"
+#include "nsThread.h"
+
+namespace mozilla::gfx {
+
+class CanvasRenderThread final {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DELETE_ON_MAIN_THREAD(
+      CanvasRenderThread)
+
+ public:
+  /// Can be called from any thread, may return nullptr late in shutdown.
+  static CanvasRenderThread* Get();
+
+  /// Can only be called from the main thread, expected to be called at most
+  /// once during a process' lifetime.
+  static void Start();
+
+  /// Can only be called from the main thread.
+  static void ShutDown();
+
+  /// Can be called from any thread.
+  static bool IsInCanvasRenderThread();
+
+  /// Can be called from any thread, may return nullptr late in shutdown.
+  static already_AddRefed<nsIThread> GetCanvasRenderThread();
+
+ private:
+  explicit CanvasRenderThread(RefPtr<nsIThread> aThread);
+  ~CanvasRenderThread();
+
+  void PostRunnable(already_AddRefed<nsIRunnable> aRunnable);
+
+  RefPtr<nsIThread> const mThread;
+};
+
+}  // namespace mozilla::gfx
+
+#endif  // _include_gfx_ipc_CanvasRenderThread_h__
diff --git a/gfx/ipc/CompositorOptions.h b/gfx/ipc/CompositorOptions.h
new file mode 100644
index 0000000000..42b7e361d6
--- /dev/null
+++ b/gfx/ipc/CompositorOptions.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 _include_mozilla_gfx_ipc_CompositorOptions_h_
+#define _include_mozilla_gfx_ipc_CompositorOptions_h_
+
+namespace IPC {
+template <typename>
+struct ParamTraits;
+}  // namespace IPC
+
+namespace mozilla {
+namespace layers {
+
+/**
+ * This class holds options that are "per compositor" - that is, these options
+ * affect a particular CompositorBridgeParent and all the content that it
+ * renders.
+ *
+ * This class is intended to be created by a platform widget (but NOT
+ * PuppetWidget) and passed to the graphics code during initialization of the
+ * top level compositor associated with that widget. The options are immutable
+ * after creation. The CompositorBridgeParent holds the canonical version of
+ * the options, but they may be accessed by other parts of the code as needed,
+ * and are accessible to content processes over PCompositorBridge as well.
+ */
+class CompositorOptions {
+ public:
+  // This constructor needed for IPDL purposes, don't use it anywhere else.
+  CompositorOptions() = default;
+
+  CompositorOptions(bool aUseAPZ, bool aUseSoftwareWebRender)
+      : mUseAPZ(aUseAPZ), mUseSoftwareWebRender(aUseSoftwareWebRender) {}
+
+  bool UseAPZ() const { return mUseAPZ; }
+  bool UseSoftwareWebRender() const { return mUseSoftwareWebRender; }
+  bool AllowSoftwareWebRenderD3D11() const {
+    return mAllowSoftwareWebRenderD3D11;
+  }
+  bool AllowSoftwareWebRenderOGL() const { return mAllowSoftwareWebRenderOGL; }
+  bool InitiallyPaused() const { return mInitiallyPaused; }
+  bool NeedFastSnaphot() const { return mNeedFastSnaphot; }
+
+  void SetUseAPZ(bool aUseAPZ) { mUseAPZ = aUseAPZ; }
+
+  void SetAllowSoftwareWebRenderD3D11(bool aAllowSoftwareWebRenderD3D11) {
+    mAllowSoftwareWebRenderD3D11 = aAllowSoftwareWebRenderD3D11;
+  }
+
+  void SetAllowSoftwareWebRenderOGL(bool aAllowSoftwareWebRenderOGL) {
+    mAllowSoftwareWebRenderOGL = aAllowSoftwareWebRenderOGL;
+  }
+
+  void SetInitiallyPaused(bool aPauseAtStartup) {
+    mInitiallyPaused = aPauseAtStartup;
+  }
+
+  void SetNeedFastSnaphot(bool aNeedFastSnaphot) {
+    mNeedFastSnaphot = aNeedFastSnaphot;
+  }
+
+  bool EqualsIgnoringApzEnablement(const CompositorOptions& aOther) const {
+    return mUseSoftwareWebRender == aOther.mUseSoftwareWebRender &&
+           mAllowSoftwareWebRenderD3D11 ==
+               aOther.mAllowSoftwareWebRenderD3D11 &&
+           mAllowSoftwareWebRenderOGL == aOther.mAllowSoftwareWebRenderOGL &&
+           mInitiallyPaused == aOther.mInitiallyPaused &&
+           mNeedFastSnaphot == aOther.mNeedFastSnaphot;
+  }
+
+  bool operator==(const CompositorOptions& aOther) const {
+    return mUseAPZ == aOther.mUseAPZ && EqualsIgnoringApzEnablement(aOther);
+  }
+
+  friend struct IPC::ParamTraits<CompositorOptions>;
+
+ private:
+  bool mUseAPZ = false;
+  bool mUseSoftwareWebRender = false;
+  bool mAllowSoftwareWebRenderD3D11 = false;
+  bool mAllowSoftwareWebRenderOGL = false;
+  bool mInitiallyPaused = false;
+  bool mNeedFastSnaphot = false;
+
+  // Make sure to add new fields to the ParamTraits implementation
+  // in LayersMessageUtils.h
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_CompositorOptions_h_
diff --git a/gfx/ipc/CompositorSession.cpp b/gfx/ipc/CompositorSession.cpp
new file mode 100644
index 0000000000..bdc7ce7019
--- /dev/null
+++ b/gfx/ipc/CompositorSession.cpp
@@ -0,0 +1,35 @@
+/* -*- 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 "CompositorSession.h"
+#include "base/process_util.h"
+#include "GPUChild.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/gfx/GPUProcessHost.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+
+namespace mozilla {
+namespace layers {
+
+using namespace gfx;
+
+CompositorSession::CompositorSession(nsBaseWidget* aWidget,
+                                     CompositorWidgetDelegate* aDelegate,
+                                     CompositorBridgeChild* aChild,
+                                     const LayersId& aRootLayerTreeId)
+    : mWidget(aWidget),
+      mCompositorWidgetDelegate(aDelegate),
+      mCompositorBridgeChild(aChild),
+      mRootLayerTreeId(aRootLayerTreeId) {}
+
+CompositorSession::~CompositorSession() = default;
+
+CompositorBridgeChild* CompositorSession::GetCompositorBridgeChild() {
+  return mCompositorBridgeChild;
+}
+
+}  // namespace layers
+}  // namespace mozilla
diff --git a/gfx/ipc/CompositorSession.h b/gfx/ipc/CompositorSession.h
new file mode 100644
index 0000000000..88b2231546
--- /dev/null
+++ b/gfx/ipc/CompositorSession.h
@@ -0,0 +1,105 @@
+/* -*- 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 _include_mozilla_gfx_ipc_CompositorSession_h_
+#define _include_mozilla_gfx_ipc_CompositorSession_h_
+
+#include "base/basictypes.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/layers/CompositorTypes.h"
+#include "nsISupportsImpl.h"
+#if defined(MOZ_WIDGET_ANDROID)
+#  include "mozilla/layers/UiCompositorControllerChild.h"
+#endif  // defined(MOZ_WIDGET_ANDROID)
+
+class nsBaseWidget;
+
+namespace mozilla {
+namespace widget {
+class CompositorWidget;
+class CompositorWidgetDelegate;
+}  // namespace widget
+namespace gfx {
+class GPUProcessHost;
+class GPUProcessManager;
+}  // namespace gfx
+namespace layers {
+
+class GeckoContentController;
+class IAPZCTreeManager;
+class CompositorBridgeParent;
+class CompositorBridgeChild;
+class ClientLayerManager;
+
+// A CompositorSession provides access to a compositor without exposing whether
+// or not it's in-process or out-of-process.
+class CompositorSession {
+  friend class gfx::GPUProcessManager;
+
+ protected:
+  typedef gfx::GPUProcessHost GPUProcessHost;
+  typedef widget::CompositorWidget CompositorWidget;
+  typedef widget::CompositorWidgetDelegate CompositorWidgetDelegate;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorSession)
+
+  virtual void Shutdown() = 0;
+
+  // This returns a CompositorBridgeParent if the compositor resides in the same
+  // process.
+  virtual CompositorBridgeParent* GetInProcessBridge() const = 0;
+
+  // Set the GeckoContentController for the root of the layer tree.
+  virtual void SetContentController(GeckoContentController* aController) = 0;
+
+  // Return the Async Pan/Zoom Tree Manager for this compositor.
+  virtual RefPtr<IAPZCTreeManager> GetAPZCTreeManager() const = 0;
+
+  // Return the child end of the compositor IPC bridge.
+  CompositorBridgeChild* GetCompositorBridgeChild();
+
+  // Return the proxy for accessing the compositor's widget.
+  CompositorWidgetDelegate* GetCompositorWidgetDelegate() {
+    return mCompositorWidgetDelegate;
+  }
+
+  // Return the id of the root layer tree.
+  LayersId RootLayerTreeId() const { return mRootLayerTreeId; }
+
+#if defined(MOZ_WIDGET_ANDROID)
+  // Set the UiCompositorControllerChild after Session creation so the Session
+  // constructor doesn't get mucked up for other platforms.
+  void SetUiCompositorControllerChild(
+      RefPtr<UiCompositorControllerChild> aUiController) {
+    mUiCompositorControllerChild = aUiController;
+  }
+
+  RefPtr<UiCompositorControllerChild> GetUiCompositorControllerChild() {
+    return mUiCompositorControllerChild;
+  }
+#endif  // defined(MOZ_WIDGET_ANDROID)
+ protected:
+  CompositorSession(nsBaseWidget* aWidget, CompositorWidgetDelegate* aDelegate,
+                    CompositorBridgeChild* aChild,
+                    const LayersId& aRootLayerTreeId);
+  virtual ~CompositorSession();
+
+ protected:
+  nsBaseWidget* mWidget;
+  CompositorWidgetDelegate* mCompositorWidgetDelegate;
+  RefPtr<CompositorBridgeChild> mCompositorBridgeChild;
+  LayersId mRootLayerTreeId;
+#if defined(MOZ_WIDGET_ANDROID)
+  RefPtr<UiCompositorControllerChild> mUiCompositorControllerChild;
+#endif  // defined(MOZ_WIDGET_ANDROID)
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CompositorSession);
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_CompositorSession_h_
diff --git a/gfx/ipc/CompositorWidgetVsyncObserver.cpp b/gfx/ipc/CompositorWidgetVsyncObserver.cpp
new file mode 100644
index 0000000000..a552e02ae6
--- /dev/null
+++ b/gfx/ipc/CompositorWidgetVsyncObserver.cpp
@@ -0,0 +1,32 @@
+/* -*- 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 "CompositorWidgetVsyncObserver.h"
+#include "mozilla/gfx/VsyncBridgeChild.h"
+
+namespace mozilla {
+namespace widget {
+
+CompositorWidgetVsyncObserver::CompositorWidgetVsyncObserver(
+    RefPtr<VsyncBridgeChild> aVsyncBridge,
+    const layers::LayersId& aRootLayerTreeId)
+    : mVsyncBridge(aVsyncBridge), mRootLayerTreeId(aRootLayerTreeId) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+CompositorWidgetVsyncObserver::~CompositorWidgetVsyncObserver() = default;
+
+void CompositorWidgetVsyncObserver::NotifyVsync(const VsyncEvent& aVsync) {
+  // Vsync notifications should only arrive on the vsync thread.
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  mVsyncBridge->NotifyVsync(aVsync, mRootLayerTreeId);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/gfx/ipc/CompositorWidgetVsyncObserver.h b/gfx/ipc/CompositorWidgetVsyncObserver.h
new file mode 100644
index 0000000000..880536c572
--- /dev/null
+++ b/gfx/ipc/CompositorWidgetVsyncObserver.h
@@ -0,0 +1,41 @@
+/* -*- 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_ipc_CompositorWidgetVsyncObserver_h
+#define mozilla_gfx_ipc_CompositorWidgetVsyncObserver_h
+
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/VsyncDispatcher.h"
+
+namespace mozilla {
+namespace gfx {
+class VsyncBridgeChild;
+}  // namespace gfx
+
+namespace widget {
+
+class CompositorWidgetVsyncObserver : public VsyncObserver {
+  typedef gfx::VsyncBridgeChild VsyncBridgeChild;
+
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorWidgetVsyncObserver, override)
+
+ public:
+  CompositorWidgetVsyncObserver(RefPtr<VsyncBridgeChild> aVsyncBridge,
+                                const layers::LayersId& aRootLayerTreeId);
+
+  void NotifyVsync(const VsyncEvent& aVsync) override;
+
+ private:
+  ~CompositorWidgetVsyncObserver() override;
+
+  RefPtr<VsyncBridgeChild> mVsyncBridge;
+  layers::LayersId mRootLayerTreeId;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_ipc_CompositorWidgetVsyncObserver_h
diff --git a/gfx/ipc/CrossProcessPaint.cpp b/gfx/ipc/CrossProcessPaint.cpp
new file mode 100644
index 0000000000..cf01ff7866
--- /dev/null
+++ b/gfx/ipc/CrossProcessPaint.cpp
@@ -0,0 +1,526 @@
+/* -*- 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 "CrossProcessPaint.h"
+
+#include "mozilla/dom/CanonicalBrowsingContext.h"
+#include "mozilla/dom/ContentProcessManager.h"
+#include "mozilla/dom/ImageBitmap.h"
+#include "mozilla/dom/BrowserParent.h"
+#include "mozilla/dom/PWindowGlobalParent.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+#include "mozilla/dom/WindowGlobalChild.h"
+#include "mozilla/dom/WindowGlobalActorsBinding.h"
+#include "mozilla/gfx/DrawEventRecorder.h"
+#include "mozilla/gfx/InlineTranslator.h"
+#include "mozilla/Logging.h"
+#include "mozilla/PresShell.h"
+
+#include "gfxPlatform.h"
+
+#include "nsContentUtils.h"
+#include "nsGlobalWindowInner.h"
+#include "nsIDocShell.h"
+#include "nsPresContext.h"
+
+static mozilla::LazyLogModule gCrossProcessPaintLog("CrossProcessPaint");
+static mozilla::LazyLogModule gPaintFragmentLog("PaintFragment");
+
+#define CPP_LOG(msg, ...) \
+  MOZ_LOG(gCrossProcessPaintLog, LogLevel::Debug, (msg, ##__VA_ARGS__))
+#define PF_LOG(msg, ...) \
+  MOZ_LOG(gPaintFragmentLog, LogLevel::Debug, (msg, ##__VA_ARGS__))
+
+namespace mozilla {
+namespace gfx {
+
+using namespace mozilla::ipc;
+
+/// The minimum scale we allow tabs to be rasterized at.
+static const float kMinPaintScale = 0.05f;
+
+/* static */
+PaintFragment PaintFragment::Record(dom::BrowsingContext* aBc,
+                                    const Maybe<IntRect>& aRect, float aScale,
+                                    nscolor aBackgroundColor,
+                                    CrossProcessPaintFlags aFlags) {
+  nsIDocShell* ds = aBc->GetDocShell();
+  if (!ds) {
+    PF_LOG("Couldn't find docshell.\n");
+    return PaintFragment{};
+  }
+
+  RefPtr<nsPresContext> presContext = ds->GetPresContext();
+  if (!presContext) {
+    PF_LOG("Couldn't find PresContext.\n");
+    return PaintFragment{};
+  }
+
+  CSSIntRect rect;
+  if (!aRect) {
+    nsCOMPtr<nsIWidget> widget =
+        nsContentUtils::WidgetForDocument(presContext->Document());
+
+    // TODO: Apply some sort of clipping to visible bounds here (Bug 1562720)
+    LayoutDeviceIntRect boundsDevice = widget->GetBounds();
+    boundsDevice.MoveTo(0, 0);
+    nsRect boundsAu = LayoutDevicePixel::ToAppUnits(
+        boundsDevice, presContext->AppUnitsPerDevPixel());
+    rect = gfx::RoundedOut(CSSPixel::FromAppUnits(boundsAu));
+  } else {
+    rect = CSSIntRect::FromUnknownRect(*aRect);
+  }
+
+  if (rect.IsEmpty()) {
+    // TODO: Should we return an empty surface here?
+    PF_LOG("Empty rect to paint.\n");
+    return PaintFragment{};
+  }
+
+  // FIXME: Shouldn't the surface size be in device rather than CSS pixels?
+  CSSIntSize surfaceSize = rect.Size();
+  surfaceSize.width *= aScale;
+  surfaceSize.height *= aScale;
+
+  CPP_LOG(
+      "Recording "
+      "[browsingContext=%p, "
+      "rect=(%d, %d) x (%d, %d), "
+      "scale=%f, "
+      "color=(%u, %u, %u, %u)]\n",
+      aBc, rect.x, rect.y, rect.width, rect.height, aScale,
+      NS_GET_R(aBackgroundColor), NS_GET_G(aBackgroundColor),
+      NS_GET_B(aBackgroundColor), NS_GET_A(aBackgroundColor));
+
+  // Check for invalid sizes
+  if (surfaceSize.width <= 0 || surfaceSize.height <= 0 ||
+      !Factory::CheckSurfaceSize(surfaceSize.ToUnknownSize())) {
+    PF_LOG("Invalid surface size of (%d x %d).\n", surfaceSize.width,
+           surfaceSize.height);
+    return PaintFragment{};
+  }
+
+  // Flush any pending notifications
+  nsContentUtils::FlushLayoutForTree(ds->GetWindow());
+
+  // Initialize the recorder
+  SurfaceFormat format = SurfaceFormat::B8G8R8A8;
+  RefPtr<DrawTarget> referenceDt = Factory::CreateDrawTarget(
+      gfxPlatform::GetPlatform()->GetSoftwareBackend(), IntSize(1, 1), format);
+
+  // TODO: This may OOM crash if the content is complex enough
+  RefPtr<DrawEventRecorderMemory> recorder =
+      MakeAndAddRef<DrawEventRecorderMemory>(nullptr);
+  RefPtr<DrawTarget> dt = Factory::CreateRecordingDrawTarget(
+      recorder, referenceDt,
+      IntRect(IntPoint(0, 0), surfaceSize.ToUnknownSize()));
+  if (!dt || !dt->IsValid()) {
+    PF_LOG("Failed to create drawTarget.\n");
+    return PaintFragment{};
+  }
+
+  RenderDocumentFlags renderDocFlags = RenderDocumentFlags::None;
+  if (!(aFlags & CrossProcessPaintFlags::DrawView)) {
+    renderDocFlags |= RenderDocumentFlags::IgnoreViewportScrolling |
+                      RenderDocumentFlags::DocumentRelative;
+    if (aFlags & CrossProcessPaintFlags::ResetScrollPosition) {
+      renderDocFlags |= RenderDocumentFlags::ResetViewportScrolling;
+    }
+  }
+  if (aFlags & CrossProcessPaintFlags::UseHighQualityScaling) {
+    renderDocFlags |= RenderDocumentFlags::UseHighQualityScaling;
+  }
+
+  // Perform the actual rendering
+  {
+    nsRect r = CSSPixel::ToAppUnits(rect);
+
+    // This matches what nsDeviceContext::CreateRenderingContext does.
+    if (presContext->IsPrintingOrPrintPreview()) {
+      dt->AddUserData(&sDisablePixelSnapping, (void*)0x1, nullptr);
+    }
+
+    gfxContext thebes(dt);
+    thebes.SetMatrix(Matrix::Scaling(aScale, aScale));
+    thebes.SetCrossProcessPaintScale(aScale);
+    RefPtr<PresShell> presShell = presContext->PresShell();
+    Unused << presShell->RenderDocument(r, renderDocFlags, aBackgroundColor,
+                                        &thebes);
+  }
+
+  if (!recorder->mOutputStream.mValid) {
+    return PaintFragment{};
+  }
+
+  ByteBuf recording = ByteBuf((uint8_t*)recorder->mOutputStream.mData,
+                              recorder->mOutputStream.mLength,
+                              recorder->mOutputStream.mCapacity);
+  recorder->mOutputStream.mData = nullptr;
+  recorder->mOutputStream.mLength = 0;
+  recorder->mOutputStream.mCapacity = 0;
+
+  return PaintFragment{
+      surfaceSize.ToUnknownSize(),
+      std::move(recording),
+      std::move(recorder->TakeDependentSurfaces()),
+  };
+}
+
+bool PaintFragment::IsEmpty() const {
+  return !mRecording.mData || mRecording.mLen == 0 || mSize == IntSize(0, 0);
+}
+
+PaintFragment::PaintFragment(IntSize aSize, ByteBuf&& aRecording,
+                             nsTHashSet<uint64_t>&& aDependencies)
+    : mSize(aSize),
+      mRecording(std::move(aRecording)),
+      mDependencies(std::move(aDependencies)) {}
+
+static dom::TabId GetTabId(dom::WindowGlobalParent* aWGP) {
+  // There is no unique TabId for a given WindowGlobalParent, as multiple
+  // WindowGlobalParents share the same PBrowser actor. However, we only
+  // ever queue one paint per PBrowser by just using the current
+  // WindowGlobalParent for a PBrowser. So we can interchange TabId and
+  // WindowGlobalParent when dealing with resolving surfaces.
+  RefPtr<dom::BrowserParent> browserParent = aWGP->GetBrowserParent();
+  return browserParent ? browserParent->GetTabId() : dom::TabId(0);
+}
+
+/* static */
+bool CrossProcessPaint::Start(dom::WindowGlobalParent* aRoot,
+                              const dom::DOMRect* aRect, float aScale,
+                              nscolor aBackgroundColor,
+                              CrossProcessPaintFlags aFlags,
+                              dom::Promise* aPromise) {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  aScale = std::max(aScale, kMinPaintScale);
+
+  CPP_LOG(
+      "Starting paint. "
+      "[wgp=%p, "
+      "scale=%f, "
+      "color=(%u, %u, %u, %u)]\n",
+      aRoot, aScale, NS_GET_R(aBackgroundColor), NS_GET_G(aBackgroundColor),
+      NS_GET_B(aBackgroundColor), NS_GET_A(aBackgroundColor));
+
+  Maybe<IntRect> rect;
+  if (aRect) {
+    rect =
+        Some(IntRect::RoundOut((float)aRect->X(), (float)aRect->Y(),
+                               (float)aRect->Width(), (float)aRect->Height()));
+  }
+
+  if (rect && rect->IsEmpty()) {
+    return false;
+  }
+
+  dom::TabId rootId = GetTabId(aRoot);
+
+  RefPtr<CrossProcessPaint> resolver =
+      new CrossProcessPaint(aScale, rootId, aFlags);
+  RefPtr<CrossProcessPaint::ResolvePromise> promise;
+  if (aRoot->IsInProcess()) {
+    RefPtr<dom::WindowGlobalChild> childActor = aRoot->GetChildActor();
+    if (!childActor) {
+      return false;
+    }
+
+    // `BrowsingContext()` cannot be nullptr.
+    RefPtr<dom::BrowsingContext> bc = childActor->BrowsingContext();
+
+    promise = resolver->Init();
+    resolver->mPendingFragments += 1;
+    resolver->ReceiveFragment(
+        aRoot,
+        PaintFragment::Record(bc, rect, aScale, aBackgroundColor, aFlags));
+  } else {
+    promise = resolver->Init();
+    resolver->QueuePaint(aRoot, rect, aBackgroundColor, aFlags);
+  }
+
+  promise->Then(
+      GetMainThreadSerialEventTarget(), __func__,
+      [promise = RefPtr{aPromise}, rootId](ResolvedFragmentMap&& aFragments) {
+        RefPtr<RecordedDependentSurface> root = aFragments.Get(rootId);
+        CPP_LOG("Resolved all fragments.\n");
+
+        // Create the destination draw target
+        RefPtr<DrawTarget> drawTarget =
+            gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
+                root->mSize, SurfaceFormat::B8G8R8A8);
+        if (!drawTarget || !drawTarget->IsValid()) {
+          CPP_LOG("Couldn't create (%d x %d) surface for fragment %" PRIu64
+                  ".\n",
+                  root->mSize.width, root->mSize.height, (uint64_t)rootId);
+          promise->MaybeReject(NS_ERROR_FAILURE);
+          return;
+        }
+
+        // Translate the recording using our child tabs
+        {
+          InlineTranslator translator(drawTarget, nullptr);
+          translator.SetDependentSurfaces(&aFragments);
+          if (!translator.TranslateRecording((char*)root->mRecording.mData,
+                                             root->mRecording.mLen)) {
+            CPP_LOG("Couldn't translate recording for fragment %" PRIu64 ".\n",
+                    (uint64_t)rootId);
+            promise->MaybeReject(NS_ERROR_FAILURE);
+            return;
+          }
+        }
+
+        RefPtr<SourceSurface> snapshot = drawTarget->Snapshot();
+        if (!snapshot) {
+          promise->MaybeReject(NS_ERROR_FAILURE);
+          return;
+        }
+
+        ErrorResult rv;
+        RefPtr<dom::ImageBitmap> bitmap =
+            dom::ImageBitmap::CreateFromSourceSurface(
+                promise->GetParentObject(), snapshot, rv);
+
+        if (!rv.Failed()) {
+          CPP_LOG("Success, fulfilling promise.\n");
+          promise->MaybeResolve(bitmap);
+        } else {
+          CPP_LOG("Couldn't create ImageBitmap for SourceSurface.\n");
+          promise->MaybeReject(std::move(rv));
+        }
+      },
+      [promise = RefPtr{aPromise}](const nsresult& aRv) {
+        promise->MaybeReject(aRv);
+      });
+
+  return true;
+}
+
+/* static */
+RefPtr<CrossProcessPaint::ResolvePromise> CrossProcessPaint::Start(
+    nsTHashSet<uint64_t>&& aDependencies) {
+  MOZ_ASSERT(!aDependencies.IsEmpty());
+  RefPtr<CrossProcessPaint> resolver =
+      new CrossProcessPaint(1.0, dom::TabId(0), CrossProcessPaintFlags::None);
+
+  RefPtr<CrossProcessPaint::ResolvePromise> promise = resolver->Init();
+
+  PaintFragment rootFragment;
+  rootFragment.mDependencies = std::move(aDependencies);
+
+  resolver->QueueDependencies(rootFragment.mDependencies);
+  resolver->mReceivedFragments.InsertOrUpdate(dom::TabId(0),
+                                              std::move(rootFragment));
+
+  resolver->MaybeResolve();
+
+  return promise;
+}
+
+CrossProcessPaint::CrossProcessPaint(float aScale, dom::TabId aRoot,
+                                     CrossProcessPaintFlags aFlags)
+    : mRoot{aRoot}, mScale{aScale}, mPendingFragments{0}, mFlags{aFlags} {}
+
+CrossProcessPaint::~CrossProcessPaint() = default;
+
+void CrossProcessPaint::ReceiveFragment(dom::WindowGlobalParent* aWGP,
+                                        PaintFragment&& aFragment) {
+  if (IsCleared()) {
+    CPP_LOG("Ignoring fragment from %p.\n", aWGP);
+    return;
+  }
+
+  dom::TabId surfaceId = GetTabId(aWGP);
+
+  MOZ_ASSERT(mPendingFragments > 0);
+  MOZ_ASSERT(!mReceivedFragments.Contains(surfaceId));
+
+  // Double check our invariants to protect against a compromised content
+  // process
+  if (mPendingFragments == 0 || mReceivedFragments.Contains(surfaceId) ||
+      aFragment.IsEmpty()) {
+    CPP_LOG("Dropping invalid fragment from %p.\n", aWGP);
+    LostFragment(aWGP);
+    return;
+  }
+
+  CPP_LOG("Receiving fragment from %p(%" PRIu64 ").\n", aWGP,
+          (uint64_t)surfaceId);
+
+  // Queue paints for child tabs
+  QueueDependencies(aFragment.mDependencies);
+
+  mReceivedFragments.InsertOrUpdate(surfaceId, std::move(aFragment));
+  mPendingFragments -= 1;
+
+  // Resolve this paint if we have received all pending fragments
+  MaybeResolve();
+}
+
+void CrossProcessPaint::LostFragment(dom::WindowGlobalParent* aWGP) {
+  if (IsCleared()) {
+    CPP_LOG("Ignoring lost fragment from %p.\n", aWGP);
+    return;
+  }
+
+  Clear(NS_ERROR_LOSS_OF_SIGNIFICANT_DATA);
+}
+
+void CrossProcessPaint::QueueDependencies(
+    const nsTHashSet<uint64_t>& aDependencies) {
+  dom::ContentProcessManager* cpm = dom::ContentProcessManager::GetSingleton();
+  if (!cpm) {
+    CPP_LOG(
+        "Skipping QueueDependencies with no"
+        " current ContentProcessManager.\n");
+    return;
+  }
+  for (const auto& key : aDependencies) {
+    auto dependency = dom::TabId(key);
+
+    // Get the current BrowserParent of the remote browser that was marked
+    // as a dependency
+    dom::ContentParentId cpId = cpm->GetTabProcessId(dependency);
+    RefPtr<dom::BrowserParent> browser =
+        cpm->GetBrowserParentByProcessAndTabId(cpId, dependency);
+    if (!browser) {
+      CPP_LOG("Skipping dependency %" PRIu64
+              " with no current BrowserParent.\n",
+              (uint64_t)dependency);
+      continue;
+    }
+
+    // Note that if the remote document is currently being cloned, it's possible
+    // that the BrowserParent isn't the one for the cloned document, but the
+    // BrowsingContext should be persisted/consistent.
+    QueuePaint(browser->GetBrowsingContext());
+  }
+}
+
+void CrossProcessPaint::QueuePaint(dom::WindowGlobalParent* aWGP,
+                                   const Maybe<IntRect>& aRect,
+                                   nscolor aBackgroundColor,
+                                   CrossProcessPaintFlags aFlags) {
+  MOZ_ASSERT(!mReceivedFragments.Contains(GetTabId(aWGP)));
+
+  CPP_LOG("Queueing paint for WindowGlobalParent(%p).\n", aWGP);
+
+  aWGP->DrawSnapshotInternal(this, aRect, mScale, aBackgroundColor,
+                             (uint32_t)aFlags);
+  mPendingFragments += 1;
+}
+
+void CrossProcessPaint::QueuePaint(dom::CanonicalBrowsingContext* aBc) {
+  RefPtr<GenericNonExclusivePromise> clonePromise = aBc->GetClonePromise();
+
+  if (!clonePromise) {
+    RefPtr<dom::WindowGlobalParent> wgp = aBc->GetCurrentWindowGlobal();
+    if (!wgp) {
+      CPP_LOG("Skipping BrowsingContext(%p) with no current WGP.\n", aBc);
+      return;
+    }
+
+    // TODO: Apply some sort of clipping to visible bounds here (Bug 1562720)
+    QueuePaint(wgp, Nothing(), NS_RGBA(0, 0, 0, 0), GetFlagsForDependencies());
+    return;
+  }
+
+  CPP_LOG("Queueing paint for BrowsingContext(%p).\n", aBc);
+  // In the case it's still in the process of cloning the remote document, we
+  // should defer the snapshot request after the cloning has been finished.
+  mPendingFragments += 1;
+  clonePromise->Then(
+      GetMainThreadSerialEventTarget(), __func__,
+      [self = RefPtr{this}, bc = RefPtr{aBc}]() {
+        RefPtr<dom::WindowGlobalParent> wgp = bc->GetCurrentWindowGlobal();
+        if (!wgp) {
+          CPP_LOG("Skipping BrowsingContext(%p) with no current WGP.\n",
+                  bc.get());
+          return;
+        }
+        MOZ_ASSERT(!self->mReceivedFragments.Contains(GetTabId(wgp)));
+
+        // TODO: Apply some sort of clipping to visible bounds here (Bug
+        // 1562720)
+        wgp->DrawSnapshotInternal(self, Nothing(), self->mScale,
+                                  NS_RGBA(0, 0, 0, 0),
+                                  (uint32_t)self->GetFlagsForDependencies());
+      },
+      [self = RefPtr{this}]() {
+        CPP_LOG(
+            "Abort painting for BrowsingContext(%p) because cloning remote "
+            "document failed.\n",
+            self.get());
+        self->Clear(NS_ERROR_FAILURE);
+      });
+}
+
+void CrossProcessPaint::Clear(nsresult aStatus) {
+  mPendingFragments = 0;
+  mReceivedFragments.Clear();
+  mPromise.RejectIfExists(aStatus, __func__);
+}
+
+bool CrossProcessPaint::IsCleared() const { return mPromise.IsEmpty(); }
+
+void CrossProcessPaint::MaybeResolve() {
+  // Don't do anything if we aren't ready, experienced an error, or already
+  // resolved this paint
+  if (IsCleared() || mPendingFragments > 0) {
+    CPP_LOG("Not ready to resolve yet, have %u fragments left.\n",
+            mPendingFragments);
+    return;
+  }
+
+  CPP_LOG("Starting to resolve fragments.\n");
+
+  // Resolve the paint fragments from the bottom up
+  ResolvedFragmentMap resolved;
+  {
+    nsresult rv = ResolveInternal(mRoot, &resolved);
+    if (NS_FAILED(rv)) {
+      CPP_LOG("Couldn't resolve.\n");
+      Clear(rv);
+      return;
+    }
+  }
+
+  CPP_LOG("Resolved all fragments.\n");
+
+  mPromise.ResolveIfExists(std::move(resolved), __func__);
+  Clear(NS_OK);
+}
+
+nsresult CrossProcessPaint::ResolveInternal(dom::TabId aTabId,
+                                            ResolvedFragmentMap* aResolved) {
+  // We should not have resolved this paint already
+  MOZ_ASSERT(!aResolved->GetWeak(aTabId));
+
+  CPP_LOG("Resolving fragment %" PRIu64 ".\n", (uint64_t)aTabId);
+
+  Maybe<PaintFragment> fragment = mReceivedFragments.Extract(aTabId);
+  if (!fragment) {
+    return NS_ERROR_LOSS_OF_SIGNIFICANT_DATA;
+  }
+
+  // Rasterize all the dependencies first so that we can resolve this fragment
+  for (const auto& key : fragment->mDependencies) {
+    auto dependency = dom::TabId(key);
+
+    nsresult rv = ResolveInternal(dependency, aResolved);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  RefPtr<RecordedDependentSurface> surface = new RecordedDependentSurface{
+      fragment->mSize, std::move(fragment->mRecording)};
+  aResolved->InsertOrUpdate(aTabId, std::move(surface));
+  return NS_OK;
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/CrossProcessPaint.h b/gfx/ipc/CrossProcessPaint.h
new file mode 100644
index 0000000000..55dc9a8b04
--- /dev/null
+++ b/gfx/ipc/CrossProcessPaint.h
@@ -0,0 +1,189 @@
+/* -*- 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 _include_mozilla_gfx_ipc_CrossProcessPaint_h_
+#define _include_mozilla_gfx_ipc_CrossProcessPaint_h_
+
+#include "nsISupportsImpl.h"
+
+#include "mozilla/dom/ipc/IdType.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/RecordedEvent.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/ipc/ByteBuf.h"
+#include "nsColor.h"
+#include "nsTHashMap.h"
+#include "nsHashKeys.h"
+#include "nsRefPtrHashtable.h"
+#include "nsTHashSet.h"
+
+class nsIDocShell;
+
+namespace IPC {
+template <typename T>
+struct ParamTraits;
+}  // namespace IPC
+
+namespace mozilla {
+
+namespace dom {
+class CanonicalBrowsingContext;
+class DOMRect;
+class Promise;
+class WindowGlobalParent;
+}  // namespace dom
+
+namespace gfx {
+
+class CrossProcessPaint;
+
+enum class CrossProcessPaintFlags {
+  None = 0,
+  DrawView = 1 << 1,
+  ResetScrollPosition = 1 << 2,
+  UseHighQualityScaling = 1 << 3,
+};
+
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(CrossProcessPaintFlags)
+
+/**
+ * A fragment of a paint of a cross process document tree.
+ */
+class PaintFragment final {
+ public:
+  /// Initializes an empty PaintFragment
+  PaintFragment() = default;
+
+  /**
+   * Creates a paint fragment by recording the draw commands and dependent tabs
+   * for a BrowsingContext.
+   *
+   * @param aBrowsingContext The frame to record.
+   * @param aRect The rectangle relative to the viewport to use. If no
+   *   rectangle is specified, then the whole viewport will be used.
+   * @param aScale The coordinate scale to use. The size of the resolved
+   *   surface will be `aRect.Size() * aScale`, with aScale clamped to
+   *   at least kMinPaintScale.
+   * @param aBackgroundColor The background color to use.
+   *
+   * @return A paint fragment. The paint fragment may be `empty` if rendering
+   *         was unable to be accomplished for some reason.
+   */
+  static PaintFragment Record(dom::BrowsingContext* aBc,
+                              const Maybe<IntRect>& aRect, float aScale,
+                              nscolor aBackgroundColor,
+                              CrossProcessPaintFlags aFlags);
+
+  /// Returns whether this paint fragment contains a valid recording.
+  bool IsEmpty() const;
+
+  PaintFragment(PaintFragment&&) = default;
+  PaintFragment& operator=(PaintFragment&&) = default;
+
+ protected:
+  friend struct mozilla::ipc::IPDLParamTraits<PaintFragment>;
+  friend CrossProcessPaint;
+
+  typedef mozilla::ipc::ByteBuf ByteBuf;
+
+  PaintFragment(IntSize, ByteBuf&&, nsTHashSet<uint64_t>&&);
+
+  IntSize mSize;
+  ByteBuf mRecording;
+  nsTHashSet<uint64_t> mDependencies;
+};
+
+/**
+ * An object for painting a cross process document tree.
+ */
+class CrossProcessPaint final {
+  NS_INLINE_DECL_REFCOUNTING(CrossProcessPaint);
+
+ public:
+  typedef nsRefPtrHashtable<nsUint64HashKey, RecordedDependentSurface>
+      ResolvedFragmentMap;
+  typedef MozPromise<ResolvedFragmentMap, nsresult, true> ResolvePromise;
+  /**
+   * Begin an asynchronous paint of a cross process document tree starting at
+   * a WindowGlobalParent. A maybe-async paint for the root WGP will be done,
+   * then async paints will be recursively queued for remote subframes. Once
+   * all subframes have been recorded, the final image will be resolved, and
+   * the promise will be resolved with a dom::ImageBitmap.
+   *
+   * @param aRoot The WindowGlobalParent to paint.
+   * @param aRect The rectangle relative to the viewport to use, or null to
+   *   render the whole viewport.
+   * @param aScale The coordinate scale to use. The size of the resolved
+   *   surface will be `aRect.Size() * aScale`, with aScale clamped to
+   *   at least kMinPaintScale. See the implementation for the current
+   *   minimum value.
+   * @param aBackgroundColor The background color to use.
+   * @param aPromise The promise to resolve with a dom::ImageBitmap.
+   *
+   * @returns Whether the paint was able to be initiated or not.
+   */
+  static bool Start(dom::WindowGlobalParent* aRoot, const dom::DOMRect* aRect,
+                    float aScale, nscolor aBackgroundColor,
+                    CrossProcessPaintFlags aFlags, dom::Promise* aPromise);
+
+  static RefPtr<ResolvePromise> Start(nsTHashSet<uint64_t>&& aDependencies);
+
+  void ReceiveFragment(dom::WindowGlobalParent* aWGP,
+                       PaintFragment&& aFragment);
+  void LostFragment(dom::WindowGlobalParent* aWGP);
+
+ private:
+  typedef nsTHashMap<nsUint64HashKey, PaintFragment> ReceivedFragmentMap;
+
+  CrossProcessPaint(float aScale, dom::TabId aRoot,
+                    CrossProcessPaintFlags aFlags);
+  ~CrossProcessPaint();
+
+  void QueueDependencies(const nsTHashSet<uint64_t>& aDependencies);
+
+  void QueuePaint(
+      dom::WindowGlobalParent* aWGP, const Maybe<IntRect>& aRect,
+      nscolor aBackgroundColor = NS_RGBA(0, 0, 0, 0),
+      CrossProcessPaintFlags aFlags = CrossProcessPaintFlags::DrawView);
+
+  void QueuePaint(dom::CanonicalBrowsingContext* aBc);
+
+  /// Clear the state of this paint so that it cannot be resolved or receive
+  /// any paint fragments.
+  void Clear(nsresult aStatus);
+
+  /// Returns if this paint has been cleared.
+  bool IsCleared() const;
+
+  /// Resolves the paint fragments if we have none pending and resolves the
+  /// promise.
+  void MaybeResolve();
+  nsresult ResolveInternal(dom::TabId aTabId, ResolvedFragmentMap* aResolved);
+
+  RefPtr<ResolvePromise> Init() {
+    MOZ_ASSERT(mPromise.IsEmpty());
+    return mPromise.Ensure(__func__);
+  }
+
+  // UseHighQualityScaling is the only flag that dependencies inherit, and we
+  // always want to use DrawView for dependencies.
+  CrossProcessPaintFlags GetFlagsForDependencies() const {
+    return (mFlags & CrossProcessPaintFlags::UseHighQualityScaling) |
+           CrossProcessPaintFlags::DrawView;
+  }
+
+  MozPromiseHolder<ResolvePromise> mPromise;
+  dom::TabId mRoot;
+  float mScale;
+  uint32_t mPendingFragments;
+  ReceivedFragmentMap mReceivedFragments;
+  CrossProcessPaintFlags mFlags;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_CrossProcessPaint_h_
diff --git a/gfx/ipc/D3DMessageUtils.cpp b/gfx/ipc/D3DMessageUtils.cpp
new file mode 100644
index 0000000000..0d18d2ed00
--- /dev/null
+++ b/gfx/ipc/D3DMessageUtils.cpp
@@ -0,0 +1,71 @@
+/* -*- 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 "D3DMessageUtils.h"
+#if defined(XP_WIN)
+#  include "gfxWindowsPlatform.h"
+#endif
+
+bool DxgiAdapterDesc::operator==(const DxgiAdapterDesc& aOther) const {
+  return memcmp(&aOther, this, sizeof(*this)) == 0;
+}
+
+#if defined(XP_WIN)
+static_assert(sizeof(DxgiAdapterDesc) == sizeof(DXGI_ADAPTER_DESC),
+              "DXGI_ADAPTER_DESC doe snot match DxgiAdapterDesc");
+
+const DxgiAdapterDesc& DxgiAdapterDesc::From(const DXGI_ADAPTER_DESC& aDesc) {
+  return reinterpret_cast<const DxgiAdapterDesc&>(aDesc);
+}
+
+const DXGI_ADAPTER_DESC& DxgiAdapterDesc::ToDesc() const {
+  return reinterpret_cast<const DXGI_ADAPTER_DESC&>(*this);
+}
+#endif
+
+namespace IPC {
+
+void ParamTraits<DxgiAdapterDesc>::Write(MessageWriter* aWriter,
+                                         const paramType& aParam) {
+#if defined(XP_WIN)
+  aWriter->WriteBytes(aParam.Description, sizeof(aParam.Description));
+  WriteParam(aWriter, aParam.VendorId);
+  WriteParam(aWriter, aParam.DeviceId);
+  WriteParam(aWriter, aParam.SubSysId);
+  WriteParam(aWriter, aParam.Revision);
+  WriteParam(aWriter, aParam.DedicatedVideoMemory);
+  WriteParam(aWriter, aParam.DedicatedSystemMemory);
+  WriteParam(aWriter, aParam.SharedSystemMemory);
+  WriteParam(aWriter, aParam.AdapterLuid.LowPart);
+  WriteParam(aWriter, aParam.AdapterLuid.HighPart);
+#endif
+}
+
+bool ParamTraits<DxgiAdapterDesc>::Read(MessageReader* aReader,
+                                        paramType* aResult) {
+#if defined(XP_WIN)
+  if (!aReader->ReadBytesInto(aResult->Description,
+                              sizeof(aResult->Description))) {
+    return false;
+  }
+
+  if (ReadParam(aReader, &aResult->VendorId) &&
+      ReadParam(aReader, &aResult->DeviceId) &&
+      ReadParam(aReader, &aResult->SubSysId) &&
+      ReadParam(aReader, &aResult->Revision) &&
+      ReadParam(aReader, &aResult->DedicatedVideoMemory) &&
+      ReadParam(aReader, &aResult->DedicatedSystemMemory) &&
+      ReadParam(aReader, &aResult->SharedSystemMemory) &&
+      ReadParam(aReader, &aResult->AdapterLuid.LowPart) &&
+      ReadParam(aReader, &aResult->AdapterLuid.HighPart)) {
+    return true;
+  }
+  return false;
+#else
+  return true;
+#endif
+}
+
+}  // namespace IPC
diff --git a/gfx/ipc/D3DMessageUtils.h b/gfx/ipc/D3DMessageUtils.h
new file mode 100644
index 0000000000..60f4d24452
--- /dev/null
+++ b/gfx/ipc/D3DMessageUtils.h
@@ -0,0 +1,46 @@
+/* -*- 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 _include_gfx_ipc_D3DMessageUtils_h__
+#define _include_gfx_ipc_D3DMessageUtils_h__
+
+#include "chrome/common/ipc_message_utils.h"
+#include "ipc/IPCMessageUtils.h"
+
+// Can't include dxgi.h, since it leaks random identifiers and #defines, and
+// IPDL causes this file to be #included all over.
+typedef struct DXGI_ADAPTER_DESC DXGI_ADAPTER_DESC;
+
+struct DxgiAdapterDesc {
+#if defined(XP_WIN)
+  WCHAR Description[128];
+  UINT VendorId;
+  UINT DeviceId;
+  UINT SubSysId;
+  UINT Revision;
+  SIZE_T DedicatedVideoMemory;
+  SIZE_T DedicatedSystemMemory;
+  SIZE_T SharedSystemMemory;
+  LUID AdapterLuid;
+
+  static const DxgiAdapterDesc& From(const DXGI_ADAPTER_DESC& aDesc);
+  const DXGI_ADAPTER_DESC& ToDesc() const;
+#endif
+
+  bool operator==(const DxgiAdapterDesc& aOther) const;
+};
+
+namespace IPC {
+
+template <>
+struct ParamTraits<DxgiAdapterDesc> {
+  typedef DxgiAdapterDesc paramType;
+  static void Write(MessageWriter* aWriter, const paramType& aParam);
+  static bool Read(MessageReader* aReader, paramType* aResult);
+};
+
+}  // namespace IPC
+
+#endif  // _include_gfx_ipc_D3DMessageUtils_h__
diff --git a/gfx/ipc/GPUChild.cpp b/gfx/ipc/GPUChild.cpp
new file mode 100644
index 0000000000..7dca827069
--- /dev/null
+++ b/gfx/ipc/GPUChild.cpp
@@ -0,0 +1,366 @@
+/* -*- 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 "GPUChild.h"
+
+#include "GPUProcessHost.h"
+#include "GPUProcessManager.h"
+#include "GfxInfoBase.h"
+#include "VRProcessManager.h"
+#include "gfxConfig.h"
+#include "gfxPlatform.h"
+#include "mozilla/Components.h"
+#include "mozilla/FOGIPC.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TelemetryIPC.h"
+#include "mozilla/dom/CheckerboardReportService.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/MemoryReportRequest.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/gfx/gfxVars.h"
+#if defined(XP_WIN)
+#  include "mozilla/gfx/DeviceManagerDx.h"
+#endif
+#include "mozilla/HangDetails.h"
+#include "mozilla/RemoteDecoderManagerChild.h"  // For RemoteDecodeIn
+#include "mozilla/Unused.h"
+#include "mozilla/ipc/Endpoint.h"
+#include "mozilla/layers/APZInputBridgeChild.h"
+#include "mozilla/layers/LayerTreeOwnerTracker.h"
+#include "nsHashPropertyBag.h"
+#include "nsIGfxInfo.h"
+#include "nsIObserverService.h"
+#include "nsIPropertyBag2.h"
+#include "ProfilerParent.h"
+
+namespace mozilla {
+namespace gfx {
+
+using namespace layers;
+
+GPUChild::GPUChild(GPUProcessHost* aHost) : mHost(aHost), mGPUReady(false) {}
+
+GPUChild::~GPUChild() = default;
+
+void GPUChild::Init() {
+  nsTArray<GfxVarUpdate> updates = gfxVars::FetchNonDefaultVars();
+
+  DevicePrefs devicePrefs;
+  devicePrefs.hwCompositing() = gfxConfig::GetValue(Feature::HW_COMPOSITING);
+  devicePrefs.d3d11Compositing() =
+      gfxConfig::GetValue(Feature::D3D11_COMPOSITING);
+  devicePrefs.oglCompositing() =
+      gfxConfig::GetValue(Feature::OPENGL_COMPOSITING);
+  devicePrefs.useD2D1() = gfxConfig::GetValue(Feature::DIRECT2D);
+  devicePrefs.d3d11HwAngle() = gfxConfig::GetValue(Feature::D3D11_HW_ANGLE);
+
+  nsTArray<LayerTreeIdMapping> mappings;
+  LayerTreeOwnerTracker::Get()->Iterate(
+      [&](LayersId aLayersId, base::ProcessId aProcessId) {
+        mappings.AppendElement(LayerTreeIdMapping(aLayersId, aProcessId));
+      });
+
+  nsCOMPtr<nsIGfxInfo> gfxInfo = components::GfxInfo::Service();
+  nsTArray<GfxInfoFeatureStatus> features;
+  if (gfxInfo) {
+    auto* gfxInfoRaw = static_cast<widget::GfxInfoBase*>(gfxInfo.get());
+    features = gfxInfoRaw->GetAllFeatures();
+  }
+
+  SendInit(updates, devicePrefs, mappings, features,
+           GPUProcessManager::Get()->AllocateNamespace());
+
+  gfxVars::AddReceiver(this);
+
+  Unused << SendInitProfiler(ProfilerParent::CreateForProcess(OtherPid()));
+}
+
+void GPUChild::OnVarChanged(const GfxVarUpdate& aVar) { SendUpdateVar(aVar); }
+
+bool GPUChild::EnsureGPUReady() {
+  // On our initial process launch, we want to block on the GetDeviceStatus
+  // message. Additionally, we may have updated our compositor configuration
+  // through the gfxVars after fallback, in which case we want to ensure the
+  // GPU process has handled any updates before creating compositor sessions.
+  if (mGPUReady && !mWaitForVarUpdate) {
+    return true;
+  }
+
+  GPUDeviceData data;
+  if (!SendGetDeviceStatus(&data)) {
+    return false;
+  }
+
+  // Only import and collect telemetry for the initial GPU process launch.
+  if (!mGPUReady) {
+    gfxPlatform::GetPlatform()->ImportGPUDeviceData(data);
+    Telemetry::AccumulateTimeDelta(Telemetry::GPU_PROCESS_LAUNCH_TIME_MS_2,
+                                   mHost->GetLaunchTime());
+    mGPUReady = true;
+  }
+
+  mWaitForVarUpdate = false;
+  return true;
+}
+
+void GPUChild::OnUnexpectedShutdown() { mUnexpectedShutdown = true; }
+
+mozilla::ipc::IPCResult GPUChild::RecvInitComplete(const GPUDeviceData& aData) {
+  // We synchronously requested GPU parameters before this arrived.
+  if (mGPUReady) {
+    return IPC_OK();
+  }
+
+  gfxPlatform::GetPlatform()->ImportGPUDeviceData(aData);
+  Telemetry::AccumulateTimeDelta(Telemetry::GPU_PROCESS_LAUNCH_TIME_MS_2,
+                                 mHost->GetLaunchTime());
+  mGPUReady = true;
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvDeclareStable() {
+  mHost->mListener->OnProcessDeclaredStable();
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvReportCheckerboard(
+    const uint32_t& aSeverity, const nsCString& aLog) {
+  layers::CheckerboardEventStorage::Report(aSeverity, std::string(aLog.get()));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvGraphicsError(const nsCString& aError) {
+  gfx::LogForwarder* lf = gfx::Factory::GetLogForwarder();
+  if (lf) {
+    std::stringstream message;
+    message << "GP+" << aError.get();
+    lf->UpdateStringsVector(message.str());
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvCreateVRProcess() {
+  // Make sure create VR process at the main process
+  MOZ_ASSERT(XRE_IsParentProcess());
+  if (StaticPrefs::dom_vr_process_enabled_AtStartup()) {
+    VRProcessManager::Initialize();
+    VRProcessManager* vr = VRProcessManager::Get();
+    MOZ_ASSERT(vr, "VRProcessManager must be initialized first.");
+
+    if (vr) {
+      vr->LaunchVRProcess();
+    }
+  }
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvShutdownVRProcess() {
+  // Make sure stopping VR process at the main process
+  MOZ_ASSERT(XRE_IsParentProcess());
+  if (StaticPrefs::dom_vr_process_enabled_AtStartup()) {
+    VRProcessManager::Shutdown();
+  }
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvNotifyUiObservers(
+    const nsCString& aTopic) {
+  nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService();
+  MOZ_ASSERT(obsSvc);
+  if (obsSvc) {
+    obsSvc->NotifyObservers(nullptr, aTopic.get(), nullptr);
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvAccumulateChildHistograms(
+    nsTArray<HistogramAccumulation>&& aAccumulations) {
+  TelemetryIPC::AccumulateChildHistograms(Telemetry::ProcessID::Gpu,
+                                          aAccumulations);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvAccumulateChildKeyedHistograms(
+    nsTArray<KeyedHistogramAccumulation>&& aAccumulations) {
+  TelemetryIPC::AccumulateChildKeyedHistograms(Telemetry::ProcessID::Gpu,
+                                               aAccumulations);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvUpdateChildScalars(
+    nsTArray<ScalarAction>&& aScalarActions) {
+  TelemetryIPC::UpdateChildScalars(Telemetry::ProcessID::Gpu, aScalarActions);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvUpdateChildKeyedScalars(
+    nsTArray<KeyedScalarAction>&& aScalarActions) {
+  TelemetryIPC::UpdateChildKeyedScalars(Telemetry::ProcessID::Gpu,
+                                        aScalarActions);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvRecordChildEvents(
+    nsTArray<mozilla::Telemetry::ChildEventData>&& aEvents) {
+  TelemetryIPC::RecordChildEvents(Telemetry::ProcessID::Gpu, aEvents);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvRecordDiscardedData(
+    const mozilla::Telemetry::DiscardedData& aDiscardedData) {
+  TelemetryIPC::RecordDiscardedData(Telemetry::ProcessID::Gpu, aDiscardedData);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvNotifyDeviceReset(
+    const GPUDeviceData& aData) {
+  gfxPlatform::GetPlatform()->ImportGPUDeviceData(aData);
+  mHost->mListener->OnRemoteProcessDeviceReset(mHost);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvNotifyOverlayInfo(
+    const OverlayInfo aInfo) {
+  gfxPlatform::GetPlatform()->SetOverlayInfo(aInfo);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvNotifySwapChainInfo(
+    const SwapChainInfo aInfo) {
+  gfxPlatform::GetPlatform()->SetSwapChainInfo(aInfo);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvFlushMemory(const nsString& aReason) {
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    os->NotifyObservers(nullptr, "memory-pressure", aReason.get());
+  }
+  return IPC_OK();
+}
+
+bool GPUChild::SendRequestMemoryReport(const uint32_t& aGeneration,
+                                       const bool& aAnonymize,
+                                       const bool& aMinimizeMemoryUsage,
+                                       const Maybe<FileDescriptor>& aDMDFile) {
+  mMemoryReportRequest = MakeUnique<MemoryReportRequestHost>(aGeneration);
+
+  PGPUChild::SendRequestMemoryReport(
+      aGeneration, aAnonymize, aMinimizeMemoryUsage, aDMDFile,
+      [&](const uint32_t& aGeneration2) {
+        if (GPUProcessManager* gpm = GPUProcessManager::Get()) {
+          if (GPUChild* child = gpm->GetGPUChild()) {
+            if (child->mMemoryReportRequest) {
+              child->mMemoryReportRequest->Finish(aGeneration2);
+              child->mMemoryReportRequest = nullptr;
+            }
+          }
+        }
+      },
+      [&](mozilla::ipc::ResponseRejectReason) {
+        if (GPUProcessManager* gpm = GPUProcessManager::Get()) {
+          if (GPUChild* child = gpm->GetGPUChild()) {
+            child->mMemoryReportRequest = nullptr;
+          }
+        }
+      });
+
+  return true;
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvAddMemoryReport(
+    const MemoryReport& aReport) {
+  if (mMemoryReportRequest) {
+    mMemoryReportRequest->RecvReport(aReport);
+  }
+  return IPC_OK();
+}
+
+void GPUChild::ActorDestroy(ActorDestroyReason aWhy) {
+  if (aWhy == AbnormalShutdown || mUnexpectedShutdown) {
+    nsAutoString dumpId;
+    GenerateCrashReport(OtherPid(), &dumpId);
+
+    Telemetry::Accumulate(
+        Telemetry::SUBPROCESS_ABNORMAL_ABORT,
+        nsDependentCString(XRE_GeckoProcessTypeToString(GeckoProcessType_GPU)),
+        1);
+
+    // Notify the Telemetry environment so that we can refresh and do a
+    // subsession split. This also notifies the crash reporter on geckoview.
+    if (nsCOMPtr<nsIObserverService> obsvc = services::GetObserverService()) {
+      RefPtr<nsHashPropertyBag> props = new nsHashPropertyBag();
+      props->SetPropertyAsBool(u"abnormal"_ns, true);
+      props->SetPropertyAsAString(u"dumpID"_ns, dumpId);
+      obsvc->NotifyObservers((nsIPropertyBag2*)props,
+                             "compositor:process-aborted", nullptr);
+    }
+  }
+
+  gfxVars::RemoveReceiver(this);
+  mHost->OnChannelClosed();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvUpdateFeature(
+    const Feature& aFeature, const FeatureFailure& aChange) {
+  gfxConfig::SetFailed(aFeature, aChange.status(), aChange.message().get(),
+                       aChange.failureId());
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvUsedFallback(const Fallback& aFallback,
+                                                   const nsCString& aMessage) {
+  gfxConfig::EnableFallback(aFallback, aMessage.get());
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvBHRThreadHang(
+    const HangDetails& aDetails) {
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    // Copy the HangDetails recieved over the network into a nsIHangDetails, and
+    // then fire our own observer notification.
+    // XXX: We should be able to avoid this potentially expensive copy here by
+    // moving our deserialized argument.
+    nsCOMPtr<nsIHangDetails> hangDetails =
+        new nsHangDetails(HangDetails(aDetails), PersistedToDisk::No);
+    obs->NotifyObservers(hangDetails, "bhr-thread-hang", nullptr);
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvUpdateMediaCodecsSupported(
+    const media::MediaCodecsSupported& aSupported) {
+  dom::ContentParent::BroadcastMediaCodecsSupportedUpdate(
+      RemoteDecodeIn::GpuProcess, aSupported);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUChild::RecvFOGData(ByteBuf&& aBuf) {
+  glean::FOGData(std::move(aBuf));
+  return IPC_OK();
+}
+
+class DeferredDeleteGPUChild : public Runnable {
+ public:
+  explicit DeferredDeleteGPUChild(RefPtr<GPUChild>&& aChild)
+      : Runnable("gfx::DeferredDeleteGPUChild"), mChild(std::move(aChild)) {}
+
+  NS_IMETHODIMP Run() override { return NS_OK; }
+
+ private:
+  RefPtr<GPUChild> mChild;
+};
+
+/* static */
+void GPUChild::Destroy(RefPtr<GPUChild>&& aChild) {
+  NS_DispatchToMainThread(new DeferredDeleteGPUChild(std::move(aChild)));
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/GPUChild.h b/gfx/ipc/GPUChild.h
new file mode 100644
index 0000000000..90672f63cc
--- /dev/null
+++ b/gfx/ipc/GPUChild.h
@@ -0,0 +1,107 @@
+/* -*- 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 _include_mozilla_gfx_ipc_GPUChild_h_
+#define _include_mozilla_gfx_ipc_GPUChild_h_
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/ipc/CrashReporterHelper.h"
+#include "mozilla/gfx/PGPUChild.h"
+#include "mozilla/gfx/gfxVarReceiver.h"
+
+namespace mozilla {
+
+namespace dom {
+class MemoryReportRequestHost;
+}  // namespace dom
+namespace gfx {
+
+class GPUProcessHost;
+
+class GPUChild final : public ipc::CrashReporterHelper<GeckoProcessType_GPU>,
+                       public PGPUChild,
+                       public gfxVarReceiver {
+  typedef mozilla::dom::MemoryReportRequestHost MemoryReportRequestHost;
+
+ public:
+  NS_INLINE_DECL_REFCOUNTING(GPUChild, final)
+
+  explicit GPUChild(GPUProcessHost* aHost);
+
+  void Init();
+
+  bool EnsureGPUReady();
+  void MarkWaitForVarUpdate() { mWaitForVarUpdate = true; }
+
+  // Notifies that an unexpected GPU process shutdown has been noticed by a
+  // different IPDL actor, and the GPU process is being torn down as a result.
+  // ActorDestroy may receive either NormalShutdown or AbnormalShutdown as a
+  // reason, depending on timings, but either way we treat the shutdown as
+  // abnormal.
+  void OnUnexpectedShutdown();
+
+  // gfxVarReceiver overrides.
+  void OnVarChanged(const GfxVarUpdate& aVar) override;
+
+  // PGPUChild overrides.
+  mozilla::ipc::IPCResult RecvInitComplete(const GPUDeviceData& aData);
+  mozilla::ipc::IPCResult RecvDeclareStable();
+  mozilla::ipc::IPCResult RecvReportCheckerboard(const uint32_t& aSeverity,
+                                                 const nsCString& aLog);
+  mozilla::ipc::IPCResult RecvCreateVRProcess();
+  mozilla::ipc::IPCResult RecvShutdownVRProcess();
+
+  mozilla::ipc::IPCResult RecvAccumulateChildHistograms(
+      nsTArray<HistogramAccumulation>&& aAccumulations);
+  mozilla::ipc::IPCResult RecvAccumulateChildKeyedHistograms(
+      nsTArray<KeyedHistogramAccumulation>&& aAccumulations);
+  mozilla::ipc::IPCResult RecvUpdateChildScalars(
+      nsTArray<ScalarAction>&& aScalarActions);
+  mozilla::ipc::IPCResult RecvUpdateChildKeyedScalars(
+      nsTArray<KeyedScalarAction>&& aScalarActions);
+  mozilla::ipc::IPCResult RecvRecordChildEvents(
+      nsTArray<ChildEventData>&& events);
+  mozilla::ipc::IPCResult RecvRecordDiscardedData(
+      const DiscardedData& aDiscardedData);
+
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+  mozilla::ipc::IPCResult RecvGraphicsError(const nsCString& aError);
+  mozilla::ipc::IPCResult RecvNotifyUiObservers(const nsCString& aTopic);
+  mozilla::ipc::IPCResult RecvNotifyDeviceReset(const GPUDeviceData& aData);
+  mozilla::ipc::IPCResult RecvNotifyOverlayInfo(const OverlayInfo aInfo);
+  mozilla::ipc::IPCResult RecvNotifySwapChainInfo(const SwapChainInfo aInfo);
+  mozilla::ipc::IPCResult RecvFlushMemory(const nsString& aReason);
+  mozilla::ipc::IPCResult RecvAddMemoryReport(const MemoryReport& aReport);
+  mozilla::ipc::IPCResult RecvUpdateFeature(const Feature& aFeature,
+                                            const FeatureFailure& aChange);
+  mozilla::ipc::IPCResult RecvUsedFallback(const Fallback& aFallback,
+                                           const nsCString& aMessage);
+  mozilla::ipc::IPCResult RecvBHRThreadHang(const HangDetails& aDetails);
+  mozilla::ipc::IPCResult RecvUpdateMediaCodecsSupported(
+      const media::MediaCodecsSupported& aSupported);
+  mozilla::ipc::IPCResult RecvFOGData(ByteBuf&& aBuf);
+
+  bool SendRequestMemoryReport(const uint32_t& aGeneration,
+                               const bool& aAnonymize,
+                               const bool& aMinimizeMemoryUsage,
+                               const Maybe<ipc::FileDescriptor>& aDMDFile);
+
+  static void Destroy(RefPtr<GPUChild>&& aChild);
+
+ private:
+  virtual ~GPUChild();
+
+  GPUProcessHost* mHost;
+  UniquePtr<MemoryReportRequestHost> mMemoryReportRequest;
+  bool mGPUReady;
+  bool mWaitForVarUpdate = false;
+  bool mUnexpectedShutdown = false;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_GPUChild_h_
diff --git a/gfx/ipc/GPUParent.cpp b/gfx/ipc/GPUParent.cpp
new file mode 100644
index 0000000000..90ef74fe21
--- /dev/null
+++ b/gfx/ipc/GPUParent.cpp
@@ -0,0 +1,753 @@
+/* -*- 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/. */
+
+#ifdef XP_WIN
+#  include "WMF.h"
+#  include "WMFDecoderModule.h"
+#endif
+#include "GLContextProvider.h"
+#include "GPUParent.h"
+#include "GPUProcessHost.h"
+#include "GPUProcessManager.h"
+#include "gfxGradientCache.h"
+#include "GfxInfoBase.h"
+#include "CanvasManagerParent.h"
+#include "VRGPUChild.h"
+#include "VRManager.h"
+#include "VRManagerParent.h"
+#include "VsyncBridgeParent.h"
+#include "cairo.h"
+#include "gfxConfig.h"
+#include "gfxCrashReporterUtils.h"
+#include "gfxPlatform.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Components.h"
+#include "mozilla/FOGIPC.h"
+#include "mozilla/HangDetails.h"
+#include "mozilla/PerfStats.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ProcessPriorityManager.h"
+#include "mozilla/RemoteDecoderManagerChild.h"
+#include "mozilla/RemoteDecoderManagerParent.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/dom/MemoryReportRequest.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/CanvasRenderThread.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/glean/GleanMetrics.h"
+#include "mozilla/image/ImageMemoryReporter.h"
+#include "mozilla/ipc/CrashReporterClient.h"
+#include "mozilla/ipc/ProcessChild.h"
+#include "mozilla/ipc/ProcessUtils.h"
+#include "mozilla/layers/APZInputBridgeParent.h"
+#include "mozilla/layers/APZPublicUtils.h"  // for apz::InitializeGlobalState
+#include "mozilla/layers/APZThreadUtils.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorManagerParent.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/layers/ImageBridgeParent.h"
+#include "mozilla/layers/LayerTreeOwnerTracker.h"
+#include "mozilla/layers/RemoteTextureMap.h"
+#include "mozilla/layers/UiCompositorControllerParent.h"
+#include "mozilla/layers/VideoBridgeParent.h"
+#include "mozilla/webrender/RenderThread.h"
+#include "mozilla/webrender/WebRenderAPI.h"
+#include "nsDebugImpl.h"
+#include "nsIGfxInfo.h"
+#include "nsIXULRuntime.h"
+#include "nsThreadManager.h"
+#include "nscore.h"
+#include "prenv.h"
+#include "skia/include/core/SkGraphics.h"
+#if defined(XP_WIN)
+#  include <dwrite.h>
+#  include <process.h>
+#  include <windows.h>
+
+#  include "gfxDWriteFonts.h"
+#  include "gfxWindowsPlatform.h"
+#  include "mozilla/WindowsVersion.h"
+#  include "mozilla/gfx/DeviceManagerDx.h"
+#  include "mozilla/layers/TextureD3D11.h"
+#  include "mozilla/widget/WinCompositorWindowThread.h"
+#else
+#  include <unistd.h>
+#endif
+#ifdef MOZ_WIDGET_GTK
+#  include <gtk/gtk.h>
+
+#  include "skia/include/ports/SkTypeface_cairo.h"
+#endif
+#ifdef ANDROID
+#  include "mozilla/layers/AndroidHardwareBuffer.h"
+#  include "skia/include/ports/SkTypeface_cairo.h"
+#endif
+#include "ChildProfilerController.h"
+#include "nsAppRunner.h"
+
+#if defined(MOZ_SANDBOX) && defined(MOZ_DEBUG) && defined(ENABLE_TESTS)
+#  include "mozilla/SandboxTestingChild.h"
+#endif
+
+namespace mozilla::gfx {
+
+using namespace ipc;
+using namespace layers;
+
+static GPUParent* sGPUParent;
+
+GPUParent::GPUParent() : mLaunchTime(TimeStamp::Now()) { sGPUParent = this; }
+
+GPUParent::~GPUParent() { sGPUParent = nullptr; }
+
+/* static */
+GPUParent* GPUParent::GetSingleton() {
+  MOZ_DIAGNOSTIC_ASSERT(sGPUParent);
+  return sGPUParent;
+}
+
+/* static */ bool GPUParent::MaybeFlushMemory() {
+#if defined(XP_WIN) && !defined(HAVE_64BIT_BUILD)
+  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
+  if (!XRE_IsGPUProcess()) {
+    return false;
+  }
+
+  MEMORYSTATUSEX stat;
+  stat.dwLength = sizeof(stat);
+  if (!GlobalMemoryStatusEx(&stat)) {
+    return false;
+  }
+
+  // We only care about virtual process memory space in the GPU process because
+  // the UI process is already watching total memory usage.
+  static const size_t kLowVirtualMemoryThreshold = 384 * 1024 * 1024;
+  bool lowMemory = stat.ullAvailVirtual < kLowVirtualMemoryThreshold;
+
+  // We suppress more than one low memory notification until we exit the
+  // condition. The UI process goes through more effort, reporting on-going
+  // memory pressure, but rather than try to manage a shared state, we just
+  // send one notification here to try to resolve it.
+  static bool sLowMemory = false;
+  if (lowMemory && !sLowMemory) {
+    NS_DispatchToMainThread(
+        NS_NewRunnableFunction("gfx::GPUParent::FlushMemory", []() -> void {
+          Unused << GPUParent::GetSingleton()->SendFlushMemory(
+              u"low-memory"_ns);
+        }));
+  }
+  sLowMemory = lowMemory;
+  return lowMemory;
+#else
+  return false;
+#endif
+}
+
+bool GPUParent::Init(mozilla::ipc::UntypedEndpoint&& aEndpoint,
+                     const char* aParentBuildID) {
+  // Initialize the thread manager before starting IPC. Otherwise, messages
+  // may be posted to the main thread and we won't be able to process them.
+  if (NS_WARN_IF(NS_FAILED(nsThreadManager::get().Init()))) {
+    return false;
+  }
+
+  // Now it's safe to start IPC.
+  if (NS_WARN_IF(!aEndpoint.Bind(this))) {
+    return false;
+  }
+
+  nsDebugImpl::SetMultiprocessMode("GPU");
+
+  // This must be checked before any IPDL message, which may hit sentinel
+  // errors due to parent and content processes having different
+  // versions.
+  MessageChannel* channel = GetIPCChannel();
+  if (channel && !channel->SendBuildIDsMatchMessage(aParentBuildID)) {
+    // We need to quit this process if the buildID doesn't match the parent's.
+    // This can occur when an update occurred in the background.
+    ProcessChild::QuickExit();
+  }
+
+  if (NS_FAILED(NS_InitMinimalXPCOM())) {
+    return false;
+  }
+
+  // Ensure the observer service exists.
+  ProcessPriorityManager::Init();
+
+  // Init crash reporter support.
+  CrashReporterClient::InitSingleton(this);
+
+  gfxConfig::Init();
+  gfxVars::Initialize();
+  gfxPlatform::InitNullMetadata();
+  // Ensure our Factory is initialised, mainly for gfx logging to work.
+  gfxPlatform::InitMoz2DLogging();
+#if defined(XP_WIN)
+  gfxWindowsPlatform::InitMemoryReportersForGPUProcess();
+  DeviceManagerDx::Init();
+  GpuProcessD3D11TextureMap::Init();
+#endif
+
+  CompositorThreadHolder::Start();
+  RemoteTextureMap::Init();
+  APZThreadUtils::SetControllerThread(NS_GetCurrentThread());
+  apz::InitializeGlobalState();
+  LayerTreeOwnerTracker::Initialize();
+  CompositorBridgeParent::InitializeStatics();
+  mozilla::ipc::SetThisProcessName("GPU Process");
+
+  return true;
+}
+
+void GPUParent::NotifyDeviceReset() {
+  if (!NS_IsMainThread()) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "gfx::GPUParent::NotifyDeviceReset",
+        []() -> void { GPUParent::GetSingleton()->NotifyDeviceReset(); }));
+    return;
+  }
+
+  // Reset and reinitialize the compositor devices
+#ifdef XP_WIN
+  if (!DeviceManagerDx::Get()->MaybeResetAndReacquireDevices()) {
+    // If the device doesn't need to be reset then the device
+    // has already been reset by a previous NotifyDeviceReset message.
+    return;
+  }
+#endif
+
+  // Notify the main process that there's been a device reset
+  // and that they should reset their compositors and repaint
+  GPUDeviceData data;
+  RecvGetDeviceStatus(&data);
+  Unused << SendNotifyDeviceReset(data);
+}
+
+void GPUParent::NotifyOverlayInfo(layers::OverlayInfo aInfo) {
+  if (!NS_IsMainThread()) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "gfx::GPUParent::NotifyOverlayInfo", [aInfo]() -> void {
+          GPUParent::GetSingleton()->NotifyOverlayInfo(aInfo);
+        }));
+    return;
+  }
+  Unused << SendNotifyOverlayInfo(aInfo);
+}
+
+void GPUParent::NotifySwapChainInfo(layers::SwapChainInfo aInfo) {
+  if (!NS_IsMainThread()) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "gfx::GPUParent::NotifySwapChainInfo", [aInfo]() -> void {
+          GPUParent::GetSingleton()->NotifySwapChainInfo(aInfo);
+        }));
+    return;
+  }
+  Unused << SendNotifySwapChainInfo(aInfo);
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInit(
+    nsTArray<GfxVarUpdate>&& vars, const DevicePrefs& devicePrefs,
+    nsTArray<LayerTreeIdMapping>&& aMappings,
+    nsTArray<GfxInfoFeatureStatus>&& aFeatures, uint32_t aWrNamespace) {
+  for (const auto& var : vars) {
+    gfxVars::ApplyUpdate(var);
+  }
+
+  // Inherit device preferences.
+  gfxConfig::Inherit(Feature::HW_COMPOSITING, devicePrefs.hwCompositing());
+  gfxConfig::Inherit(Feature::D3D11_COMPOSITING,
+                     devicePrefs.d3d11Compositing());
+  gfxConfig::Inherit(Feature::OPENGL_COMPOSITING, devicePrefs.oglCompositing());
+  gfxConfig::Inherit(Feature::DIRECT2D, devicePrefs.useD2D1());
+  gfxConfig::Inherit(Feature::D3D11_HW_ANGLE, devicePrefs.d3d11HwAngle());
+
+  {  // Let the crash reporter know if we've got WR enabled or not. For other
+    // processes this happens in gfxPlatform::InitWebRenderConfig.
+    ScopedGfxFeatureReporter reporter("WR",
+                                      gfxPlatform::WebRenderPrefEnabled());
+    reporter.SetSuccessful();
+  }
+
+  for (const LayerTreeIdMapping& map : aMappings) {
+    LayerTreeOwnerTracker::Get()->Map(map.layersId(), map.ownerId());
+  }
+
+  widget::GfxInfoBase::SetFeatureStatus(std::move(aFeatures));
+
+  // We bypass gfxPlatform::Init, so we must initialize any relevant libraries
+  // here that would normally be initialized there.
+  SkGraphics::Init();
+
+  if (gfxVars::RemoteCanvasEnabled()) {
+    gfxGradientCache::Init();
+  }
+
+#if defined(XP_WIN)
+  if (gfxConfig::IsEnabled(Feature::D3D11_COMPOSITING)) {
+    if (DeviceManagerDx::Get()->CreateCompositorDevices() &&
+        gfxVars::RemoteCanvasEnabled()) {
+      if (DeviceManagerDx::Get()->CreateCanvasDevice()) {
+        gfxDWriteFont::InitDWriteSupport();
+      } else {
+        gfxWarning() << "Failed to create canvas device.";
+      }
+    }
+  }
+  DeviceManagerDx::Get()->CreateDirectCompositionDevice();
+  // Ensure to initialize GfxInfo
+  nsCOMPtr<nsIGfxInfo> gfxInfo = components::GfxInfo::Service();
+  Unused << gfxInfo;
+
+  Factory::EnsureDWriteFactory();
+#endif
+
+#if defined(MOZ_WIDGET_GTK)
+  char* display_name = PR_GetEnv("MOZ_GDK_DISPLAY");
+  if (!display_name) {
+    bool waylandEnabled = false;
+#  ifdef MOZ_WAYLAND
+    waylandEnabled = IsWaylandEnabled();
+#  endif
+    if (!waylandEnabled) {
+      display_name = PR_GetEnv("DISPLAY");
+    }
+  }
+  if (display_name) {
+    int argc = 3;
+    char option_name[] = "--display";
+    char* argv[] = {// argv0 is unused because g_set_prgname() was called in
+                    // XRE_InitChildProcess().
+                    nullptr, option_name, display_name, nullptr};
+    char** argvp = argv;
+    gtk_init(&argc, &argvp);
+  } else {
+    gtk_init(nullptr, nullptr);
+  }
+
+  // Ensure we have an FT library for font instantiation.
+  // This would normally be set by gfxPlatform::Init().
+  // Since we bypass that, we must do it here instead.
+  FT_Library library = Factory::NewFTLibrary();
+  MOZ_ASSERT(library);
+  Factory::SetFTLibrary(library);
+
+  // true to match gfxPlatform::FontHintingEnabled(). We must hardcode
+  // this value because we do not have a gfxPlatform instance.
+  SkInitCairoFT(true);
+
+  // Ensure that GfxInfo::Init is called on the main thread.
+  nsCOMPtr<nsIGfxInfo> gfxInfo = components::GfxInfo::Service();
+  Unused << gfxInfo;
+#endif
+
+#ifdef ANDROID
+  // Ensure we have an FT library for font instantiation.
+  // This would normally be set by gfxPlatform::Init().
+  // Since we bypass that, we must do it here instead.
+  FT_Library library = Factory::NewFTLibrary();
+  MOZ_ASSERT(library);
+  Factory::SetFTLibrary(library);
+
+  // false to match gfxAndroidPlatform::FontHintingEnabled(). We must
+  // hardcode this value because we do not have a gfxPlatform instance.
+  SkInitCairoFT(false);
+
+  if (gfxVars::UseAHardwareBufferSharedSurfaceWebglOop()) {
+    layers::AndroidHardwareBufferApi::Init();
+    layers::AndroidHardwareBufferManager::Init();
+  }
+
+#endif
+
+  // Make sure to do this *after* we update gfxVars above.
+  if (gfxVars::UseCanvasRenderThread()) {
+    gfx::CanvasRenderThread::Start();
+  }
+  wr::RenderThread::Start(aWrNamespace);
+  image::ImageMemoryReporter::InitForWebRender();
+
+  VRManager::ManagerInit();
+  // Send a message to the UI process that we're done.
+  GPUDeviceData data;
+  RecvGetDeviceStatus(&data);
+  Unused << SendInitComplete(data);
+
+  // Dispatch a task to run when idle that will determine which codecs are
+  // usable. The primary goal is to determine if the media feature pack is
+  // installed.
+  MOZ_ALWAYS_SUCCEEDS(NS_DispatchToCurrentThreadQueue(
+      NS_NewRunnableFunction(
+          "GPUParent::Supported",
+          []() {
+            auto supported = PDMFactory::Supported();
+            Unused << GPUParent::GetSingleton()->SendUpdateMediaCodecsSupported(
+                supported);
+          }),
+      2000 /* 2 seconds timeout */, EventQueuePriority::Idle));
+
+  Telemetry::AccumulateTimeDelta(Telemetry::GPU_PROCESS_INITIALIZATION_TIME_MS,
+                                 mLaunchTime);
+  return IPC_OK();
+}
+
+#if defined(MOZ_SANDBOX) && defined(MOZ_DEBUG) && defined(ENABLE_TESTS)
+mozilla::ipc::IPCResult GPUParent::RecvInitSandboxTesting(
+    Endpoint<PSandboxTestingChild>&& aEndpoint) {
+  if (!SandboxTestingChild::Initialize(std::move(aEndpoint))) {
+    return IPC_FAIL(
+        this, "InitSandboxTesting failed to initialise the child process.");
+  }
+  return IPC_OK();
+}
+#endif
+
+mozilla::ipc::IPCResult GPUParent::RecvInitCompositorManager(
+    Endpoint<PCompositorManagerParent>&& aEndpoint) {
+  CompositorManagerParent::Create(std::move(aEndpoint), ContentParentId(),
+                                  /* aIsRoot */ true);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitVsyncBridge(
+    Endpoint<PVsyncBridgeParent>&& aVsyncEndpoint) {
+  mVsyncBridge = VsyncBridgeParent::Start(std::move(aVsyncEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitImageBridge(
+    Endpoint<PImageBridgeParent>&& aEndpoint) {
+  ImageBridgeParent::CreateForGPUProcess(std::move(aEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitVideoBridge(
+    Endpoint<PVideoBridgeParent>&& aEndpoint,
+    const layers::VideoBridgeSource& aSource) {
+  // For GPU decoding, the video bridge would be opened in
+  // `VideoBridgeChild::StartupForGPUProcess`.
+  MOZ_ASSERT(aSource == layers::VideoBridgeSource::RddProcess ||
+             aSource == layers::VideoBridgeSource::MFMediaEngineCDMProcess);
+  VideoBridgeParent::Open(std::move(aEndpoint), aSource);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitVRManager(
+    Endpoint<PVRManagerParent>&& aEndpoint) {
+  VRManagerParent::CreateForGPUProcess(std::move(aEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitVR(
+    Endpoint<PVRGPUChild>&& aEndpoint) {
+  gfx::VRGPUChild::InitForGPUProcess(std::move(aEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitUiCompositorController(
+    const LayersId& aRootLayerTreeId,
+    Endpoint<PUiCompositorControllerParent>&& aEndpoint) {
+  UiCompositorControllerParent::Start(aRootLayerTreeId, std::move(aEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitAPZInputBridge(
+    const LayersId& aRootLayerTreeId,
+    Endpoint<PAPZInputBridgeParent>&& aEndpoint) {
+  APZInputBridgeParent::Create(aRootLayerTreeId, std::move(aEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvInitProfiler(
+    Endpoint<PProfilerChild>&& aEndpoint) {
+  mProfilerController = ChildProfilerController::Create(std::move(aEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvUpdateVar(const GfxVarUpdate& aUpdate) {
+#if defined(XP_WIN)
+  auto scopeExit = MakeScopeExit(
+      [couldUseHWDecoder = gfx::gfxVars::CanUseHardwareVideoDecoding()] {
+        if (couldUseHWDecoder != gfx::gfxVars::CanUseHardwareVideoDecoding()) {
+          // The capabilities of the system may have changed, force a refresh by
+          // re-initializing the WMF PDM.
+          WMFDecoderModule::Init();
+          Unused << GPUParent::GetSingleton()->SendUpdateMediaCodecsSupported(
+              PDMFactory::Supported(true /* force refresh */));
+        }
+      });
+#endif
+  gfxVars::ApplyUpdate(aUpdate);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvPreferenceUpdate(const Pref& aPref) {
+  Preferences::SetPreference(aPref);
+  return IPC_OK();
+}
+
+static void CopyFeatureChange(Feature aFeature, Maybe<FeatureFailure>* aOut) {
+  FeatureState& feature = gfxConfig::GetFeature(aFeature);
+  if (feature.DisabledByDefault() || feature.IsEnabled()) {
+    // No change:
+    //   - Disabled-by-default means the parent process told us not to use this
+    //   feature.
+    //   - Enabled means we were told to use this feature, and we didn't
+    //   discover anything
+    //     that would prevent us from doing so.
+    *aOut = Nothing();
+    return;
+  }
+
+  MOZ_ASSERT(!feature.IsEnabled());
+
+  nsCString message;
+  message.AssignASCII(feature.GetFailureMessage());
+
+  *aOut =
+      Some(FeatureFailure(feature.GetValue(), message, feature.GetFailureId()));
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvGetDeviceStatus(GPUDeviceData* aOut) {
+  CopyFeatureChange(Feature::D3D11_COMPOSITING, &aOut->d3d11Compositing());
+  CopyFeatureChange(Feature::OPENGL_COMPOSITING, &aOut->oglCompositing());
+
+#if defined(XP_WIN)
+  if (DeviceManagerDx* dm = DeviceManagerDx::Get()) {
+    D3D11DeviceStatus deviceStatus;
+    dm->ExportDeviceInfo(&deviceStatus);
+    aOut->gpuDevice() = Some(deviceStatus);
+  }
+#else
+  aOut->gpuDevice() = Nothing();
+#endif
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvSimulateDeviceReset() {
+#if defined(XP_WIN)
+  DeviceManagerDx::Get()->ForceDeviceReset(
+      ForcedDeviceResetReason::COMPOSITOR_UPDATED);
+#endif
+  wr::RenderThread::Get()->SimulateDeviceReset();
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvNewContentCompositorManager(
+    Endpoint<PCompositorManagerParent>&& aEndpoint,
+    const ContentParentId& aChildId) {
+  CompositorManagerParent::Create(std::move(aEndpoint), aChildId,
+                                  /* aIsRoot */ false);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvNewContentImageBridge(
+    Endpoint<PImageBridgeParent>&& aEndpoint, const ContentParentId& aChildId) {
+  if (!ImageBridgeParent::CreateForContent(std::move(aEndpoint), aChildId)) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvNewContentVRManager(
+    Endpoint<PVRManagerParent>&& aEndpoint, const ContentParentId& aChildId) {
+  if (!VRManagerParent::CreateForContent(std::move(aEndpoint), aChildId)) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvNewContentRemoteDecoderManager(
+    Endpoint<PRemoteDecoderManagerParent>&& aEndpoint,
+    const ContentParentId& aChildId) {
+  if (!RemoteDecoderManagerParent::CreateForContent(std::move(aEndpoint),
+                                                    aChildId)) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvAddLayerTreeIdMapping(
+    const LayerTreeIdMapping& aMapping) {
+  LayerTreeOwnerTracker::Get()->Map(aMapping.layersId(), aMapping.ownerId());
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvRemoveLayerTreeIdMapping(
+    const LayerTreeIdMapping& aMapping) {
+  LayerTreeOwnerTracker::Get()->Unmap(aMapping.layersId(), aMapping.ownerId());
+  CompositorBridgeParent::DeallocateLayerTreeId(aMapping.layersId());
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvNotifyGpuObservers(
+    const nsCString& aTopic) {
+  nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService();
+  MOZ_ASSERT(obsSvc);
+  if (obsSvc) {
+    obsSvc->NotifyObservers(nullptr, aTopic.get(), nullptr);
+  }
+  return IPC_OK();
+}
+
+/* static */
+void GPUParent::GetGPUProcessName(nsACString& aStr) {
+  auto processType = XRE_GetProcessType();
+  unsigned pid = 0;
+  if (processType == GeckoProcessType_GPU) {
+    pid = getpid();
+  } else {
+    MOZ_DIAGNOSTIC_ASSERT(processType == GeckoProcessType_Default);
+    pid = GPUProcessManager::Get()->GPUProcessPid();
+  }
+
+  nsPrintfCString processName("GPU (pid %u)", pid);
+  aStr.Assign(processName);
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvRequestMemoryReport(
+    const uint32_t& aGeneration, const bool& aAnonymize,
+    const bool& aMinimizeMemoryUsage, const Maybe<FileDescriptor>& aDMDFile,
+    const RequestMemoryReportResolver& aResolver) {
+  nsAutoCString processName;
+  GetGPUProcessName(processName);
+
+  mozilla::dom::MemoryReportRequestClient::Start(
+      aGeneration, aAnonymize, aMinimizeMemoryUsage, aDMDFile, processName,
+      [&](const MemoryReport& aReport) {
+        Unused << GetSingleton()->SendAddMemoryReport(aReport);
+      },
+      aResolver);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvShutdownVR() {
+  if (StaticPrefs::dom_vr_process_enabled_AtStartup()) {
+    VRGPUChild::Shutdown();
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvUpdatePerfStatsCollectionMask(
+    const uint64_t& aMask) {
+  PerfStats::SetCollectionMask(static_cast<PerfStats::MetricMask>(aMask));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvCollectPerfStatsJSON(
+    CollectPerfStatsJSONResolver&& aResolver) {
+  aResolver(PerfStats::CollectLocalPerfStatsJSON());
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvFlushFOGData(
+    FlushFOGDataResolver&& aResolver) {
+  glean::FlushFOGData(std::move(aResolver));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvTestTriggerMetrics(
+    TestTriggerMetricsResolver&& aResolve) {
+  mozilla::glean::test_only_ipc::a_counter.Add(nsIXULRuntime::PROCESS_TYPE_GPU);
+  aResolve(true);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult GPUParent::RecvCrashProcess() {
+  MOZ_CRASH("Deliberate GPU process crash");
+  return IPC_OK();
+}
+
+void GPUParent::ActorDestroy(ActorDestroyReason aWhy) {
+  if (AbnormalShutdown == aWhy) {
+    NS_WARNING("Shutting down GPU process early due to a crash!");
+    ProcessChild::QuickExit();
+  }
+
+  // Send the last bits of Glean data over to the main process.
+  glean::FlushFOGData(
+      [](ByteBuf&& aBuf) { glean::SendFOGData(std::move(aBuf)); });
+
+#ifndef NS_FREE_PERMANENT_DATA
+  // No point in going through XPCOM shutdown because we don't keep persistent
+  // state.
+  ProcessChild::QuickExit();
+#endif
+
+  // Wait until all RemoteDecoderManagerParent have closed.
+  mShutdownBlockers.WaitUntilClear(10 * 1000 /* 10s timeout*/)
+      ->Then(GetCurrentSerialEventTarget(), __func__, [self = RefPtr{this}]() {
+        if (self->mProfilerController) {
+          self->mProfilerController->Shutdown();
+          self->mProfilerController = nullptr;
+        }
+
+        if (self->mVsyncBridge) {
+          self->mVsyncBridge->Shutdown();
+          self->mVsyncBridge = nullptr;
+        }
+        VideoBridgeParent::Shutdown();
+        // This could be running on either the Compositor or the Renderer
+        // thread.
+        CanvasManagerParent::Shutdown();
+        CompositorThreadHolder::Shutdown();
+        RemoteTextureMap::Shutdown();
+        // There is a case that RenderThread exists when gfxVars::UseWebRender()
+        // is false. This could happen when WebRender was fallbacked to
+        // compositor.
+        if (wr::RenderThread::Get()) {
+          wr::RenderThread::ShutDown();
+        }
+        if (gfx::CanvasRenderThread::Get()) {
+          gfx::CanvasRenderThread::ShutDown();
+        }
+#ifdef XP_WIN
+        if (widget::WinCompositorWindowThread::Get()) {
+          widget::WinCompositorWindowThread::ShutDown();
+        }
+#endif
+
+        image::ImageMemoryReporter::ShutdownForWebRender();
+
+        // Shut down the default GL context provider.
+        gl::GLContextProvider::Shutdown();
+
+#if defined(XP_WIN)
+        // The above shutdown calls operate on the available context providers
+        // on most platforms.  Windows is a "special snowflake", though, and has
+        // three context providers available, so we have to shut all of them
+        // down. We should only support the default GL provider on Windows;
+        // then, this could go away. Unfortunately, we currently support WGL
+        // (the default) for WebGL on Optimus.
+        gl::GLContextProviderEGL::Shutdown();
+#endif
+
+        Factory::ShutDown();
+
+    // We bypass gfxPlatform shutdown, so we must shutdown any libraries here
+    // that would normally be handled by it.
+#ifdef NS_FREE_PERMANENT_DATA
+        SkGraphics::PurgeFontCache();
+        cairo_debug_reset_static_data();
+#endif
+
+#if defined(XP_WIN)
+        GpuProcessD3D11TextureMap::Shutdown();
+        DeviceManagerDx::Shutdown();
+#endif
+        LayerTreeOwnerTracker::Shutdown();
+        gfxVars::Shutdown();
+        gfxConfig::Shutdown();
+        CrashReporterClient::DestroySingleton();
+        XRE_ShutdownChildProcess();
+      });
+}
+
+}  // namespace mozilla::gfx
diff --git a/gfx/ipc/GPUParent.h b/gfx/ipc/GPUParent.h
new file mode 100644
index 0000000000..7b1a5cfad0
--- /dev/null
+++ b/gfx/ipc/GPUParent.h
@@ -0,0 +1,129 @@
+/* -*- 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 _include_gfx_ipc_GPUParent_h__
+#define _include_gfx_ipc_GPUParent_h__
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/gfx/PGPUParent.h"
+#include "mozilla/ipc/AsyncBlockers.h"
+
+namespace mozilla {
+
+class TimeStamp;
+class ChildProfilerController;
+
+namespace gfx {
+
+class VsyncBridgeParent;
+
+class GPUParent final : public PGPUParent {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(GPUParent, final)
+
+  GPUParent();
+
+  static GPUParent* GetSingleton();
+
+  ipc::AsyncBlockers& AsyncShutdownService() { return mShutdownBlockers; }
+
+  // Gets the name of the GPU process, in the format expected by about:memory.
+  // There must be a GPU process active, and the caller must be either in that
+  // process or the parent process.
+  static void GetGPUProcessName(nsACString& aStr);
+
+  // Check for memory pressure and notify the parent process if necessary.
+  static bool MaybeFlushMemory();
+
+  bool Init(mozilla::ipc::UntypedEndpoint&& aEndpoint,
+            const char* aParentBuildID);
+  void NotifyDeviceReset();
+  void NotifyOverlayInfo(layers::OverlayInfo aInfo);
+  void NotifySwapChainInfo(layers::SwapChainInfo aInfo);
+
+  mozilla::ipc::IPCResult RecvInit(nsTArray<GfxVarUpdate>&& vars,
+                                   const DevicePrefs& devicePrefs,
+                                   nsTArray<LayerTreeIdMapping>&& mappings,
+                                   nsTArray<GfxInfoFeatureStatus>&& features,
+                                   uint32_t wrNamespace);
+  mozilla::ipc::IPCResult RecvInitCompositorManager(
+      Endpoint<PCompositorManagerParent>&& aEndpoint);
+  mozilla::ipc::IPCResult RecvInitVsyncBridge(
+      Endpoint<PVsyncBridgeParent>&& aVsyncEndpoint);
+  mozilla::ipc::IPCResult RecvInitImageBridge(
+      Endpoint<PImageBridgeParent>&& aEndpoint);
+  mozilla::ipc::IPCResult RecvInitVideoBridge(
+      Endpoint<PVideoBridgeParent>&& aEndpoint,
+      const layers::VideoBridgeSource& aSource);
+  mozilla::ipc::IPCResult RecvInitVRManager(
+      Endpoint<PVRManagerParent>&& aEndpoint);
+  mozilla::ipc::IPCResult RecvInitVR(Endpoint<PVRGPUChild>&& aVRGPUChild);
+  mozilla::ipc::IPCResult RecvInitUiCompositorController(
+      const LayersId& aRootLayerTreeId,
+      Endpoint<PUiCompositorControllerParent>&& aEndpoint);
+  mozilla::ipc::IPCResult RecvInitAPZInputBridge(
+      const LayersId& aRootLayerTreeId,
+      Endpoint<PAPZInputBridgeParent>&& aEndpoint);
+  mozilla::ipc::IPCResult RecvInitProfiler(
+      Endpoint<PProfilerChild>&& aEndpoint);
+  mozilla::ipc::IPCResult RecvUpdateVar(const GfxVarUpdate& pref);
+  mozilla::ipc::IPCResult RecvPreferenceUpdate(const Pref& pref);
+  mozilla::ipc::IPCResult RecvNewContentCompositorManager(
+      Endpoint<PCompositorManagerParent>&& aEndpoint,
+      const ContentParentId& aChildId);
+  mozilla::ipc::IPCResult RecvNewContentImageBridge(
+      Endpoint<PImageBridgeParent>&& aEndpoint,
+      const ContentParentId& aChildId);
+  mozilla::ipc::IPCResult RecvNewContentVRManager(
+      Endpoint<PVRManagerParent>&& aEndpoint, const ContentParentId& aChildId);
+  mozilla::ipc::IPCResult RecvNewContentRemoteDecoderManager(
+      Endpoint<PRemoteDecoderManagerParent>&& aEndpoint,
+      const ContentParentId& aChildId);
+  mozilla::ipc::IPCResult RecvGetDeviceStatus(GPUDeviceData* aOutStatus);
+  mozilla::ipc::IPCResult RecvSimulateDeviceReset();
+  mozilla::ipc::IPCResult RecvAddLayerTreeIdMapping(
+      const LayerTreeIdMapping& aMapping);
+  mozilla::ipc::IPCResult RecvRemoveLayerTreeIdMapping(
+      const LayerTreeIdMapping& aMapping);
+  mozilla::ipc::IPCResult RecvNotifyGpuObservers(const nsCString& aTopic);
+  mozilla::ipc::IPCResult RecvRequestMemoryReport(
+      const uint32_t& generation, const bool& anonymize,
+      const bool& minimizeMemoryUsage,
+      const Maybe<ipc::FileDescriptor>& DMDFile,
+      const RequestMemoryReportResolver& aResolver);
+  mozilla::ipc::IPCResult RecvShutdownVR();
+
+  mozilla::ipc::IPCResult RecvUpdatePerfStatsCollectionMask(
+      const uint64_t& aMask);
+  mozilla::ipc::IPCResult RecvCollectPerfStatsJSON(
+      CollectPerfStatsJSONResolver&& aResolver);
+
+#if defined(MOZ_SANDBOX) && defined(MOZ_DEBUG) && defined(ENABLE_TESTS)
+  mozilla::ipc::IPCResult RecvInitSandboxTesting(
+      Endpoint<PSandboxTestingChild>&& aEndpoint);
+#endif
+
+  mozilla::ipc::IPCResult RecvFlushFOGData(FlushFOGDataResolver&& aResolver);
+
+  mozilla::ipc::IPCResult RecvTestTriggerMetrics(
+      TestTriggerMetricsResolver&& aResolve);
+
+  mozilla::ipc::IPCResult RecvCrashProcess();
+
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+
+ private:
+  ~GPUParent();
+
+  const TimeStamp mLaunchTime;
+  RefPtr<VsyncBridgeParent> mVsyncBridge;
+  RefPtr<ChildProfilerController> mProfilerController;
+  ipc::AsyncBlockers mShutdownBlockers;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_gfx_ipc_GPUParent_h__
diff --git a/gfx/ipc/GPUProcessHost.cpp b/gfx/ipc/GPUProcessHost.cpp
new file mode 100644
index 0000000000..bc7237a0b9
--- /dev/null
+++ b/gfx/ipc/GPUProcessHost.cpp
@@ -0,0 +1,265 @@
+/* -*- 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 "GPUProcessHost.h"
+#include "chrome/common/process_watcher.h"
+#include "gfxPlatform.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/gfx/GPUChild.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/layers/SynchronousTask.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_layers.h"
+#include "VRGPUChild.h"
+#include "mozilla/ipc/ProcessUtils.h"
+#ifdef MOZ_WIDGET_ANDROID
+#  include "mozilla/java/GeckoProcessManagerWrappers.h"
+#endif
+
+namespace mozilla {
+namespace gfx {
+
+using namespace ipc;
+
+GPUProcessHost::GPUProcessHost(Listener* aListener)
+    : GeckoChildProcessHost(GeckoProcessType_GPU),
+      mListener(aListener),
+      mTaskFactory(this),
+      mLaunchPhase(LaunchPhase::Unlaunched),
+      mProcessToken(0),
+      mShutdownRequested(false),
+      mChannelClosed(false) {
+  MOZ_COUNT_CTOR(GPUProcessHost);
+}
+
+GPUProcessHost::~GPUProcessHost() { MOZ_COUNT_DTOR(GPUProcessHost); }
+
+bool GPUProcessHost::Launch(StringVector aExtraOpts) {
+  MOZ_ASSERT(mLaunchPhase == LaunchPhase::Unlaunched);
+  MOZ_ASSERT(!mGPUChild);
+  MOZ_ASSERT(!gfxPlatform::IsHeadless());
+
+  mPrefSerializer = MakeUnique<ipc::SharedPreferenceSerializer>();
+  if (!mPrefSerializer->SerializeToSharedMemory(GeckoProcessType_GPU,
+                                                /* remoteType */ ""_ns)) {
+    return false;
+  }
+  mPrefSerializer->AddSharedPrefCmdLineArgs(*this, aExtraOpts);
+
+#if defined(XP_WIN) && defined(MOZ_SANDBOX)
+  mSandboxLevel = Preferences::GetInt("security.sandbox.gpu.level");
+#endif
+
+  mLaunchPhase = LaunchPhase::Waiting;
+  mLaunchTime = TimeStamp::Now();
+
+  if (!GeckoChildProcessHost::AsyncLaunch(aExtraOpts)) {
+    mLaunchPhase = LaunchPhase::Complete;
+    mPrefSerializer = nullptr;
+    return false;
+  }
+  return true;
+}
+
+bool GPUProcessHost::WaitForLaunch() {
+  if (mLaunchPhase == LaunchPhase::Complete) {
+    return !!mGPUChild;
+  }
+
+  int32_t timeoutMs =
+      StaticPrefs::layers_gpu_process_startup_timeout_ms_AtStartup();
+
+  // If one of the following environment variables are set we can effectively
+  // ignore the timeout - as we can guarantee the compositor process will be
+  // terminated
+  if (PR_GetEnv("MOZ_DEBUG_CHILD_PROCESS") ||
+      PR_GetEnv("MOZ_DEBUG_CHILD_PAUSE")) {
+    timeoutMs = 0;
+  }
+
+  // Our caller expects the connection to be finished after we return, so we
+  // immediately set up the IPDL actor and fire callbacks. The IO thread will
+  // still dispatch a notification to the main thread - we'll just ignore it.
+  bool result = GeckoChildProcessHost::WaitUntilConnected(timeoutMs);
+  InitAfterConnect(result);
+  return result;
+}
+
+void GPUProcessHost::OnChannelConnected(base::ProcessId peer_pid) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  GeckoChildProcessHost::OnChannelConnected(peer_pid);
+
+  // Post a task to the main thread. Take the lock because mTaskFactory is not
+  // thread-safe.
+  RefPtr<Runnable> runnable;
+  {
+    MonitorAutoLock lock(mMonitor);
+    runnable =
+        mTaskFactory.NewRunnableMethod(&GPUProcessHost::OnChannelConnectedTask);
+  }
+  NS_DispatchToMainThread(runnable);
+}
+
+void GPUProcessHost::OnChannelError() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  GeckoChildProcessHost::OnChannelError();
+
+  // Post a task to the main thread. Take the lock because mTaskFactory is not
+  // thread-safe.
+  RefPtr<Runnable> runnable;
+  {
+    MonitorAutoLock lock(mMonitor);
+    runnable =
+        mTaskFactory.NewRunnableMethod(&GPUProcessHost::OnChannelErrorTask);
+  }
+  NS_DispatchToMainThread(runnable);
+}
+
+void GPUProcessHost::OnChannelConnectedTask() {
+  if (mLaunchPhase == LaunchPhase::Waiting) {
+    InitAfterConnect(true);
+  }
+}
+
+void GPUProcessHost::OnChannelErrorTask() {
+  if (mLaunchPhase == LaunchPhase::Waiting) {
+    InitAfterConnect(false);
+  }
+}
+
+static uint64_t sProcessTokenCounter = 0;
+
+void GPUProcessHost::InitAfterConnect(bool aSucceeded) {
+  MOZ_ASSERT(mLaunchPhase == LaunchPhase::Waiting);
+  MOZ_ASSERT(!mGPUChild);
+
+  mLaunchPhase = LaunchPhase::Complete;
+  mPrefSerializer = nullptr;
+
+  if (aSucceeded) {
+    mProcessToken = ++sProcessTokenCounter;
+    mGPUChild = MakeRefPtr<GPUChild>(this);
+    DebugOnly<bool> rv = TakeInitialEndpoint().Bind(mGPUChild.get());
+    MOZ_ASSERT(rv);
+
+    mGPUChild->Init();
+
+#ifdef MOZ_WIDGET_ANDROID
+    nsCOMPtr<nsIEventTarget> launcherThread(GetIPCLauncher());
+    MOZ_ASSERT(launcherThread);
+    layers::SynchronousTask task(
+        "GeckoProcessManager::GetCompositorSurfaceManager");
+
+    launcherThread->Dispatch(NS_NewRunnableFunction(
+        "GeckoProcessManager::GetCompositorSurfaceManager", [&]() {
+          layers::AutoCompleteTask complete(&task);
+          mCompositorSurfaceManager =
+              java::GeckoProcessManager::GetCompositorSurfaceManager();
+        }));
+
+    task.Wait();
+#endif
+  }
+
+  if (mListener) {
+    mListener->OnProcessLaunchComplete(this);
+  }
+}
+
+void GPUProcessHost::Shutdown(bool aUnexpectedShutdown) {
+  MOZ_ASSERT(!mShutdownRequested);
+
+  mListener = nullptr;
+
+  if (mGPUChild) {
+    // OnChannelClosed uses this to check if the shutdown was expected or
+    // unexpected.
+    mShutdownRequested = true;
+
+    if (aUnexpectedShutdown) {
+      mGPUChild->OnUnexpectedShutdown();
+    }
+
+    // The channel might already be closed if we got here unexpectedly.
+    if (!mChannelClosed) {
+      if (VRGPUChild::IsCreated()) {
+        VRGPUChild::Get()->Close();
+      }
+      mGPUChild->SendShutdownVR();
+      mGPUChild->Close();
+    }
+
+#ifndef NS_FREE_PERMANENT_DATA
+    // No need to communicate shutdown, the GPU process doesn't need to
+    // communicate anything back.
+    KillHard("NormalShutdown");
+#endif
+
+    // If we're shutting down unexpectedly, we're in the middle of handling an
+    // ActorDestroy for PGPUChild, which is still on the stack. We'll return
+    // back to OnChannelClosed.
+    //
+    // Otherwise, we'll wait for OnChannelClose to be called whenever PGPUChild
+    // acknowledges shutdown.
+    return;
+  }
+
+  DestroyProcess();
+}
+
+void GPUProcessHost::OnChannelClosed() {
+  mChannelClosed = true;
+
+  if (!mShutdownRequested && mListener) {
+    // This is an unclean shutdown. Notify our listener that we're going away.
+    mListener->OnProcessUnexpectedShutdown(this);
+  } else {
+    DestroyProcess();
+  }
+
+  // Release the actor.
+  GPUChild::Destroy(std::move(mGPUChild));
+  MOZ_ASSERT(!mGPUChild);
+}
+
+void GPUProcessHost::KillHard(const char* aReason) {
+  ProcessHandle handle = GetChildProcessHandle();
+  if (!base::KillProcess(handle, base::PROCESS_END_KILLED_BY_USER)) {
+    NS_WARNING("failed to kill subprocess!");
+  }
+
+  SetAlreadyDead();
+}
+
+uint64_t GPUProcessHost::GetProcessToken() const { return mProcessToken; }
+
+void GPUProcessHost::KillProcess() { KillHard("DiagnosticKill"); }
+
+void GPUProcessHost::CrashProcess() { mGPUChild->SendCrashProcess(); }
+
+void GPUProcessHost::DestroyProcess() {
+  // Cancel all tasks. We don't want anything triggering after our caller
+  // expects this to go away.
+  {
+    MonitorAutoLock lock(mMonitor);
+    mTaskFactory.RevokeAll();
+  }
+
+  GetCurrentSerialEventTarget()->Dispatch(
+      NS_NewRunnableFunction("DestroyProcessRunnable", [this] { Destroy(); }));
+}
+
+#ifdef MOZ_WIDGET_ANDROID
+java::CompositorSurfaceManager::Param
+GPUProcessHost::GetCompositorSurfaceManager() {
+  return mCompositorSurfaceManager;
+}
+#endif
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/GPUProcessHost.h b/gfx/ipc/GPUProcessHost.h
new file mode 100644
index 0000000000..cfd7a9fe46
--- /dev/null
+++ b/gfx/ipc/GPUProcessHost.h
@@ -0,0 +1,165 @@
+/* -*- 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 _include_mozilla_gfx_ipc_GPUProcessHost_h_
+#define _include_mozilla_gfx_ipc_GPUProcessHost_h_
+
+#include "mozilla/Maybe.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/ipc/TaskFactory.h"
+
+#ifdef MOZ_WIDGET_ANDROID
+#  include "mozilla/java/CompositorSurfaceManagerWrappers.h"
+#endif
+
+namespace mozilla {
+namespace ipc {
+class SharedPreferenceSerializer;
+}
+}  // namespace mozilla
+class nsITimer;
+
+namespace mozilla {
+namespace gfx {
+
+class GPUChild;
+
+// GPUProcessHost is the "parent process" container for a subprocess handle and
+// IPC connection. It owns the parent process IPDL actor, which in this case,
+// is a GPUChild.
+//
+// GPUProcessHosts are allocated and managed by GPUProcessManager. For all
+// intents and purposes it is a singleton, though more than one may be allocated
+// at a time due to its shutdown being asynchronous.
+class GPUProcessHost final : public mozilla::ipc::GeckoChildProcessHost {
+  friend class GPUChild;
+
+ public:
+  class Listener {
+   public:
+    virtual void OnProcessLaunchComplete(GPUProcessHost* aHost) {}
+
+    // The GPUProcessHost has unexpectedly shutdown or had its connection
+    // severed. This is not called if an error occurs after calling
+    // Shutdown().
+    virtual void OnProcessUnexpectedShutdown(GPUProcessHost* aHost) {}
+
+    virtual void OnRemoteProcessDeviceReset(GPUProcessHost* aHost) {}
+
+    virtual void OnProcessDeclaredStable() {}
+  };
+
+  explicit GPUProcessHost(Listener* listener);
+
+  // Launch the subprocess asynchronously. On failure, false is returned.
+  // Otherwise, true is returned, and the OnProcessLaunchComplete listener
+  // callback will be invoked either when a connection has been established, or
+  // if a connection could not be established due to an asynchronous error.
+  //
+  // @param aExtraOpts (StringVector)
+  //        Extra options to pass to the subprocess.
+  bool Launch(StringVector aExtraOpts);
+
+  // If the process is being launched, block until it has launched and
+  // connected. If a launch task is pending, it will fire immediately.
+  //
+  // Returns true if the process is successfully connected; false otherwise.
+  bool WaitForLaunch();
+
+  // Inform the process that it should clean up its resources and shut down.
+  // This initiates an asynchronous shutdown sequence. After this method
+  // returns, it is safe for the caller to forget its pointer to the
+  // GPUProcessHost.
+  //
+  // After this returns, the attached Listener is no longer used.
+  //
+  // Setting aUnexpectedShutdown = true indicates that this is being called to
+  // clean up resources in response to an unexpected shutdown having been
+  // detected.
+  void Shutdown(bool aUnexpectedShutdown = false);
+
+  // Return the actor for the top-level actor of the process. If the process
+  // has not connected yet, this returns null.
+  GPUChild* GetActor() const { return mGPUChild.get(); }
+
+  // Return a unique id for this process, guaranteed not to be shared with any
+  // past or future instance of GPUProcessHost.
+  uint64_t GetProcessToken() const;
+
+  bool IsConnected() const { return !!mGPUChild; }
+
+  // Return the time stamp for when we tried to launch the GPU process. This is
+  // currently used for Telemetry so that we can determine how long GPU
+  // processes take to spin up. Note this doesn't denote a successful launch,
+  // just when we attempted launch.
+  TimeStamp GetLaunchTime() const { return mLaunchTime; }
+
+  // Called on the IO thread.
+  void OnChannelConnected(base::ProcessId peer_pid) override;
+  void OnChannelError() override;
+
+  void SetListener(Listener* aListener);
+
+  // Kills the GPU process. Used for tests and diagnostics
+  void KillProcess();
+
+  // Causes the GPU process to crash. Used for tests and diagnostics
+  void CrashProcess();
+
+#ifdef MOZ_WIDGET_ANDROID
+  java::CompositorSurfaceManager::Param GetCompositorSurfaceManager();
+#endif
+
+ private:
+  ~GPUProcessHost();
+
+  // Called on the main thread.
+  void OnChannelConnectedTask();
+  void OnChannelErrorTask();
+
+  // Called on the main thread after a connection has been established.
+  void InitAfterConnect(bool aSucceeded);
+
+  // Called on the main thread when the mGPUChild actor is shutting down.
+  void OnChannelClosed();
+
+  // Kill the remote process, triggering IPC shutdown.
+  void KillHard(const char* aReason);
+
+  void DestroyProcess();
+
+  DISALLOW_COPY_AND_ASSIGN(GPUProcessHost);
+
+  Listener* mListener;
+  mozilla::ipc::TaskFactory<GPUProcessHost> mTaskFactory;
+
+  enum class LaunchPhase { Unlaunched, Waiting, Complete };
+  LaunchPhase mLaunchPhase;
+
+  RefPtr<GPUChild> mGPUChild;
+  uint64_t mProcessToken;
+
+  UniquePtr<mozilla::ipc::SharedPreferenceSerializer> mPrefSerializer;
+
+  bool mShutdownRequested;
+  bool mChannelClosed;
+
+  TimeStamp mLaunchTime;
+
+#ifdef MOZ_WIDGET_ANDROID
+  // Binder interface used to send compositor surfaces to GPU process. There is
+  // one instance per GPU process which gets initialized after launch, then
+  // multiple compositors can take a reference to it.
+  java::CompositorSurfaceManager::GlobalRef mCompositorSurfaceManager;
+#endif
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_GPUProcessHost_h_
diff --git a/gfx/ipc/GPUProcessImpl.cpp b/gfx/ipc/GPUProcessImpl.cpp
new file mode 100644
index 0000000000..00a5335ab6
--- /dev/null
+++ b/gfx/ipc/GPUProcessImpl.cpp
@@ -0,0 +1,48 @@
+/* -*- 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 "GPUProcessImpl.h"
+#include "mozilla/ipc/IOThreadChild.h"
+#include "nsXPCOM.h"
+#include "mozilla/ipc/ProcessUtils.h"
+#include "mozilla/GeckoArgs.h"
+
+#if defined(OS_WIN) && defined(MOZ_SANDBOX)
+#  include "mozilla/sandboxTarget.h"
+#elif defined(__OpenBSD__) && defined(MOZ_SANDBOX)
+#  include "mozilla/SandboxSettings.h"
+#endif
+
+namespace mozilla {
+namespace gfx {
+
+using namespace ipc;
+
+GPUProcessImpl::~GPUProcessImpl() = default;
+
+bool GPUProcessImpl::Init(int aArgc, char* aArgv[]) {
+#if defined(MOZ_SANDBOX) && defined(OS_WIN)
+  mozilla::SandboxTarget::Instance()->StartSandbox();
+#elif defined(__OpenBSD__) && defined(MOZ_SANDBOX)
+  StartOpenBSDSandbox(GeckoProcessType_GPU);
+#endif
+
+  Maybe<const char*> parentBuildID =
+      geckoargs::sParentBuildID.Get(aArgc, aArgv);
+  if (parentBuildID.isNothing()) {
+    return false;
+  }
+
+  if (!ProcessChild::InitPrefs(aArgc, aArgv)) {
+    return false;
+  }
+
+  return mGPU->Init(TakeInitialEndpoint(), *parentBuildID);
+}
+
+void GPUProcessImpl::CleanUp() { NS_ShutdownXPCOM(nullptr); }
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/GPUProcessImpl.h b/gfx/ipc/GPUProcessImpl.h
new file mode 100644
index 0000000000..0f188afe8a
--- /dev/null
+++ b/gfx/ipc/GPUProcessImpl.h
@@ -0,0 +1,41 @@
+/* -*- 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 _include_gfx_ipc_GPUProcessImpl_h__
+#define _include_gfx_ipc_GPUProcessImpl_h__
+
+#include "mozilla/ipc/ProcessChild.h"
+#include "GPUParent.h"
+
+#if defined(XP_WIN)
+#  include "mozilla/mscom/ProcessRuntime.h"
+#endif
+
+namespace mozilla {
+namespace gfx {
+
+// This class owns the subprocess instance of a PGPU - which in this case,
+// is a GPUParent. It is instantiated as a singleton in XRE_InitChildProcess.
+class GPUProcessImpl final : public ipc::ProcessChild {
+ public:
+  using ipc::ProcessChild::ProcessChild;
+  virtual ~GPUProcessImpl();
+
+  bool Init(int aArgc, char* aArgv[]) override;
+  void CleanUp() override;
+
+ private:
+  RefPtr<GPUParent> mGPU = new GPUParent;
+
+#if defined(XP_WIN)
+  // This object initializes and configures COM.
+  mozilla::mscom::ProcessRuntime mCOMRuntime;
+#endif
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_gfx_ipc_GPUProcessImpl_h__
diff --git a/gfx/ipc/GPUProcessListener.h b/gfx/ipc/GPUProcessListener.h
new file mode 100644
index 0000000000..a54c890ba0
--- /dev/null
+++ b/gfx/ipc/GPUProcessListener.h
@@ -0,0 +1,28 @@
+/* -*- 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 _include_mozilla_gfx_ipc_GPUProcessListener_h_
+#define _include_mozilla_gfx_ipc_GPUProcessListener_h_
+
+namespace mozilla {
+namespace gfx {
+
+class GPUProcessListener {
+ public:
+  virtual ~GPUProcessListener() = default;
+
+  // Called when the compositor has died and the rendering stack must be
+  // recreated.
+  virtual void OnCompositorUnexpectedShutdown() {}
+
+  // Called when devices have been reset and tabs must throw away their
+  // layer managers.
+  virtual void OnCompositorDeviceReset() {}
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_GPUProcessListener_h_
diff --git a/gfx/ipc/GPUProcessManager.cpp b/gfx/ipc/GPUProcessManager.cpp
new file mode 100644
index 0000000000..b310d7e6cd
--- /dev/null
+++ b/gfx/ipc/GPUProcessManager.cpp
@@ -0,0 +1,1563 @@
+/* -*- 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 "GPUProcessManager.h"
+
+#include "gfxConfig.h"
+#include "gfxPlatform.h"
+#include "GPUProcessHost.h"
+#include "GPUProcessListener.h"
+#include "mozilla/AppShutdown.h"
+#include "mozilla/MemoryReportingProcess.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Sprintf.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/StaticPrefs_media.h"
+#include "mozilla/RemoteDecoderManagerChild.h"
+#include "mozilla/RemoteDecoderManagerParent.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/gfx/GPUChild.h"
+#include "mozilla/ipc/Endpoint.h"
+#include "mozilla/ipc/ProcessChild.h"
+#include "mozilla/layers/APZCTreeManagerChild.h"
+#include "mozilla/layers/APZInputBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorManagerChild.h"
+#include "mozilla/layers/CompositorManagerParent.h"
+#include "mozilla/layers/CompositorOptions.h"
+#include "mozilla/layers/ImageBridgeChild.h"
+#include "mozilla/layers/ImageBridgeParent.h"
+#include "mozilla/layers/InProcessCompositorSession.h"
+#include "mozilla/layers/LayerTreeOwnerTracker.h"
+#include "mozilla/layers/RemoteCompositorSession.h"
+#include "mozilla/webrender/RenderThread.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsAppRunner.h"
+#include "mozilla/widget/CompositorWidget.h"
+#ifdef MOZ_WIDGET_SUPPORTS_OOP_COMPOSITING
+#  include "mozilla/widget/CompositorWidgetChild.h"
+#endif
+#include "nsBaseWidget.h"
+#include "nsContentUtils.h"
+#include "VRManagerChild.h"
+#include "VRManagerParent.h"
+#include "VsyncBridgeChild.h"
+#include "VsyncIOThreadHolder.h"
+#include "VsyncSource.h"
+#include "nsExceptionHandler.h"
+#include "nsPrintfCString.h"
+
+#if defined(MOZ_WIDGET_ANDROID)
+#  include "mozilla/java/SurfaceControlManagerWrappers.h"
+#  include "mozilla/widget/AndroidUiThread.h"
+#  include "mozilla/layers/UiCompositorControllerChild.h"
+#endif  // defined(MOZ_WIDGET_ANDROID)
+
+#if defined(XP_WIN)
+#  include "gfxWindowsPlatform.h"
+#endif
+
+namespace mozilla {
+namespace gfx {
+
+using namespace mozilla::layers;
+
+enum class FallbackType : uint32_t {
+  NONE = 0,
+  DECODINGDISABLED,
+  DISABLED,
+};
+
+static StaticAutoPtr<GPUProcessManager> sSingleton;
+
+GPUProcessManager* GPUProcessManager::Get() { return sSingleton; }
+
+void GPUProcessManager::Initialize() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  sSingleton = new GPUProcessManager();
+}
+
+void GPUProcessManager::Shutdown() { sSingleton = nullptr; }
+
+GPUProcessManager::GPUProcessManager()
+    : mTaskFactory(this),
+      mNextNamespace(0),
+      mIdNamespace(0),
+      mResourceId(0),
+      mUnstableProcessAttempts(0),
+      mTotalProcessAttempts(0),
+      mDeviceResetCount(0),
+      mAppInForeground(true),
+      mProcess(nullptr),
+      mProcessToken(0),
+      mProcessStable(true),
+      mGPUChild(nullptr) {
+  MOZ_COUNT_CTOR(GPUProcessManager);
+
+  mIdNamespace = AllocateNamespace();
+
+  mDeviceResetLastTime = TimeStamp::Now();
+
+  LayerTreeOwnerTracker::Initialize();
+  CompositorBridgeParent::InitializeStatics();
+}
+
+GPUProcessManager::~GPUProcessManager() {
+  MOZ_COUNT_DTOR(GPUProcessManager);
+
+  LayerTreeOwnerTracker::Shutdown();
+
+  // The GPU process should have already been shut down.
+  MOZ_ASSERT(!mProcess && !mGPUChild);
+
+  // We should have already removed observers.
+  MOZ_ASSERT(!mObserver);
+}
+
+NS_IMPL_ISUPPORTS(GPUProcessManager::Observer, nsIObserver);
+
+GPUProcessManager::Observer::Observer(GPUProcessManager* aManager)
+    : mManager(aManager) {}
+
+NS_IMETHODIMP
+GPUProcessManager::Observer::Observe(nsISupports* aSubject, const char* aTopic,
+                                     const char16_t* aData) {
+  if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
+    mManager->OnXPCOMShutdown();
+  } else if (!strcmp(aTopic, "nsPref:changed")) {
+    mManager->OnPreferenceChange(aData);
+  } else if (!strcmp(aTopic, "application-foreground")) {
+    mManager->mAppInForeground = true;
+    if (!mManager->mProcess && gfxConfig::IsEnabled(Feature::GPU_PROCESS)) {
+      Unused << mManager->LaunchGPUProcess();
+    }
+  } else if (!strcmp(aTopic, "application-background")) {
+    mManager->mAppInForeground = false;
+  }
+  return NS_OK;
+}
+
+void GPUProcessManager::OnXPCOMShutdown() {
+  if (mObserver) {
+    nsContentUtils::UnregisterShutdownObserver(mObserver);
+    Preferences::RemoveObserver(mObserver, "");
+    nsCOMPtr<nsIObserverService> obsServ = services::GetObserverService();
+    if (obsServ) {
+      obsServ->RemoveObserver(mObserver, "application-foreground");
+      obsServ->RemoveObserver(mObserver, "application-background");
+    }
+    mObserver = nullptr;
+  }
+
+  CleanShutdown();
+}
+
+void GPUProcessManager::OnPreferenceChange(const char16_t* aData) {
+  // We know prefs are ASCII here.
+  NS_LossyConvertUTF16toASCII strData(aData);
+
+  mozilla::dom::Pref pref(strData, /* isLocked */ false,
+                          /* isSanitized */ false, Nothing(), Nothing());
+
+  Preferences::GetPreference(&pref, GeckoProcessType_GPU,
+                             /* remoteType */ ""_ns);
+  if (!!mGPUChild) {
+    MOZ_ASSERT(mQueuedPrefs.IsEmpty());
+    mGPUChild->SendPreferenceUpdate(pref);
+  } else if (IsGPUProcessLaunching()) {
+    mQueuedPrefs.AppendElement(pref);
+  }
+}
+
+void GPUProcessManager::ResetProcessStable() {
+  mTotalProcessAttempts++;
+  mProcessStable = false;
+  mProcessAttemptLastTime = TimeStamp::Now();
+}
+
+bool GPUProcessManager::IsProcessStable(const TimeStamp& aNow) {
+  if (mTotalProcessAttempts > 0) {
+    auto delta = (int32_t)(aNow - mProcessAttemptLastTime).ToMilliseconds();
+    if (delta < StaticPrefs::layers_gpu_process_stable_min_uptime_ms()) {
+      return false;
+    }
+  }
+  return mProcessStable;
+}
+
+bool GPUProcessManager::LaunchGPUProcess() {
+  if (mProcess) {
+    return true;
+  }
+
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdown)) {
+    return false;
+  }
+
+  // Start listening for pref changes so we can
+  // forward them to the process once it is running.
+  if (!mObserver) {
+    mObserver = new Observer(this);
+    nsContentUtils::RegisterShutdownObserver(mObserver);
+    Preferences::AddStrongObserver(mObserver, "");
+    nsCOMPtr<nsIObserverService> obsServ = services::GetObserverService();
+    if (obsServ) {
+      obsServ->AddObserver(mObserver, "application-foreground", false);
+      obsServ->AddObserver(mObserver, "application-background", false);
+    }
+  }
+
+  // Start the Vsync I/O thread so can use it as soon as the process launches.
+  EnsureVsyncIOThread();
+
+  // If the process didn't live long enough, reset the stable flag so that we
+  // don't end up in a restart loop.
+  auto newTime = TimeStamp::Now();
+  if (!IsProcessStable(newTime)) {
+    mUnstableProcessAttempts++;
+  }
+  mTotalProcessAttempts++;
+  mProcessAttemptLastTime = newTime;
+  mProcessStable = false;
+
+  std::vector<std::string> extraArgs;
+  ipc::ProcessChild::AddPlatformBuildID(extraArgs);
+
+  // The subprocess is launched asynchronously, so we wait for a callback to
+  // acquire the IPDL actor.
+  mProcess = new GPUProcessHost(this);
+  if (!mProcess->Launch(extraArgs)) {
+    DisableGPUProcess("Failed to launch GPU process");
+  }
+
+  return true;
+}
+
+bool GPUProcessManager::IsGPUProcessLaunching() {
+  MOZ_ASSERT(NS_IsMainThread());
+  return !!mProcess && !mGPUChild;
+}
+
+void GPUProcessManager::DisableGPUProcess(const char* aMessage) {
+  MaybeDisableGPUProcess(aMessage, /* aAllowRestart */ false);
+}
+
+bool GPUProcessManager::MaybeDisableGPUProcess(const char* aMessage,
+                                               bool aAllowRestart) {
+  if (!gfxConfig::IsEnabled(Feature::GPU_PROCESS)) {
+    return true;
+  }
+
+  if (!aAllowRestart) {
+    gfxConfig::SetFailed(Feature::GPU_PROCESS, FeatureStatus::Failed, aMessage);
+  }
+
+  bool wantRestart;
+  if (mLastError) {
+    wantRestart =
+        FallbackFromAcceleration(mLastError.value(), mLastErrorMsg.ref());
+    mLastError.reset();
+    mLastErrorMsg.reset();
+  } else {
+    wantRestart = gfxPlatform::FallbackFromAcceleration(
+        FeatureStatus::Unavailable, "GPU Process is disabled",
+        "FEATURE_FAILURE_GPU_PROCESS_DISABLED"_ns);
+  }
+  if (aAllowRestart && wantRestart) {
+    // The fallback method can make use of the GPU process.
+    return false;
+  }
+
+  if (aAllowRestart) {
+    gfxConfig::SetFailed(Feature::GPU_PROCESS, FeatureStatus::Failed, aMessage);
+  }
+
+  MOZ_ASSERT(!gfxConfig::IsEnabled(Feature::GPU_PROCESS));
+
+  gfxCriticalNote << aMessage;
+
+  gfxPlatform::DisableGPUProcess();
+
+  Telemetry::Accumulate(Telemetry::GPU_PROCESS_CRASH_FALLBACKS,
+                        uint32_t(FallbackType::DISABLED));
+
+  DestroyProcess();
+  ShutdownVsyncIOThread();
+
+  // Now the stability state is based upon the in process compositor session.
+  ResetProcessStable();
+
+  // We may have been in the middle of guaranteeing our various services are
+  // available when one failed. Some callers may fallback to using the same
+  // process equivalent, and we need to make sure those services are setup
+  // correctly. We cannot re-enter DisableGPUProcess from this call because we
+  // know that it is disabled in the config above.
+  DebugOnly<bool> ready = EnsureProtocolsReady();
+  MOZ_ASSERT_IF(!ready,
+                AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdown));
+
+  // If we disable the GPU process during reinitialization after a previous
+  // crash, then we need to tell the content processes again, because they
+  // need to rebind to the UI process.
+  HandleProcessLost();
+  return true;
+}
+
+nsresult GPUProcessManager::EnsureGPUReady() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // We only wait to fail with NS_ERROR_ILLEGAL_DURING_SHUTDOWN if we would
+  // cause a state change or if we are in the middle of relaunching the GPU
+  // process.
+  bool inShutdown = AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdown);
+
+  // Launch the GPU process if it is enabled but hasn't been (re-)launched yet.
+  if (!mProcess && gfxConfig::IsEnabled(Feature::GPU_PROCESS)) {
+    if (NS_WARN_IF(inShutdown)) {
+      return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
+    }
+
+    if (!LaunchGPUProcess()) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+  }
+
+  if (mProcess && !mProcess->IsConnected()) {
+    if (NS_WARN_IF(inShutdown)) {
+      return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
+    }
+
+    if (!mProcess->WaitForLaunch()) {
+      // If this fails, we should have fired OnProcessLaunchComplete and
+      // removed the process.
+      MOZ_ASSERT(!mProcess && !mGPUChild);
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+  }
+
+  if (mGPUChild) {
+    if (mGPUChild->EnsureGPUReady()) {
+      return NS_OK;
+    }
+
+    // If the initialization above fails, we likely have a GPU process teardown
+    // waiting in our message queue (or will soon). We need to ensure we don't
+    // restart it later because if we fail here, our callers assume they should
+    // fall back to a combined UI/GPU process. This also ensures our internal
+    // state is consistent (e.g. process token is reset).
+    DisableGPUProcess("Failed to initialize GPU process");
+  }
+
+  // This is the first time we are trying to use the in-process compositor.
+  if (mTotalProcessAttempts == 0) {
+    if (NS_WARN_IF(inShutdown)) {
+      return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
+    }
+    ResetProcessStable();
+  }
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
+bool GPUProcessManager::EnsureProtocolsReady() {
+  return EnsureCompositorManagerChild() && EnsureImageBridgeChild() &&
+         EnsureVRManager();
+}
+
+bool GPUProcessManager::EnsureCompositorManagerChild() {
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return false;
+  }
+
+  if (CompositorManagerChild::IsInitialized(mProcessToken)) {
+    return true;
+  }
+
+  if (NS_FAILED(rv)) {
+    CompositorManagerChild::InitSameProcess(AllocateNamespace(), mProcessToken);
+    return true;
+  }
+
+  ipc::Endpoint<PCompositorManagerParent> parentPipe;
+  ipc::Endpoint<PCompositorManagerChild> childPipe;
+  rv = PCompositorManager::CreateEndpoints(
+      mGPUChild->OtherPid(), base::GetCurrentProcId(), &parentPipe, &childPipe);
+  if (NS_FAILED(rv)) {
+    DisableGPUProcess("Failed to create PCompositorManager endpoints");
+    return true;
+  }
+
+  mGPUChild->SendInitCompositorManager(std::move(parentPipe));
+  CompositorManagerChild::Init(std::move(childPipe), AllocateNamespace(),
+                               mProcessToken);
+  return true;
+}
+
+bool GPUProcessManager::EnsureImageBridgeChild() {
+  if (ImageBridgeChild::GetSingleton()) {
+    return true;
+  }
+
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return false;
+  }
+
+  if (NS_FAILED(rv)) {
+    ImageBridgeChild::InitSameProcess(AllocateNamespace());
+    return true;
+  }
+
+  ipc::Endpoint<PImageBridgeParent> parentPipe;
+  ipc::Endpoint<PImageBridgeChild> childPipe;
+  rv = PImageBridge::CreateEndpoints(
+      mGPUChild->OtherPid(), base::GetCurrentProcId(), &parentPipe, &childPipe);
+  if (NS_FAILED(rv)) {
+    DisableGPUProcess("Failed to create PImageBridge endpoints");
+    return true;
+  }
+
+  mGPUChild->SendInitImageBridge(std::move(parentPipe));
+  ImageBridgeChild::InitWithGPUProcess(std::move(childPipe),
+                                       AllocateNamespace());
+  return true;
+}
+
+bool GPUProcessManager::EnsureVRManager() {
+  if (VRManagerChild::IsCreated()) {
+    return true;
+  }
+
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return false;
+  }
+
+  if (NS_FAILED(rv)) {
+    VRManagerChild::InitSameProcess();
+    return true;
+  }
+
+  ipc::Endpoint<PVRManagerParent> parentPipe;
+  ipc::Endpoint<PVRManagerChild> childPipe;
+  rv = PVRManager::CreateEndpoints(
+      mGPUChild->OtherPid(), base::GetCurrentProcId(), &parentPipe, &childPipe);
+  if (NS_FAILED(rv)) {
+    DisableGPUProcess("Failed to create PVRManager endpoints");
+    return true;
+  }
+
+  mGPUChild->SendInitVRManager(std::move(parentPipe));
+  VRManagerChild::InitWithGPUProcess(std::move(childPipe));
+  return true;
+}
+
+#if defined(MOZ_WIDGET_ANDROID)
+already_AddRefed<UiCompositorControllerChild>
+GPUProcessManager::CreateUiCompositorController(nsBaseWidget* aWidget,
+                                                const LayersId aId) {
+  RefPtr<UiCompositorControllerChild> result;
+
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return nullptr;
+  }
+
+  if (NS_FAILED(rv)) {
+    result = UiCompositorControllerChild::CreateForSameProcess(aId, aWidget);
+  } else {
+    ipc::Endpoint<PUiCompositorControllerParent> parentPipe;
+    ipc::Endpoint<PUiCompositorControllerChild> childPipe;
+    rv = PUiCompositorController::CreateEndpoints(mGPUChild->OtherPid(),
+                                                  base::GetCurrentProcId(),
+                                                  &parentPipe, &childPipe);
+    if (NS_FAILED(rv)) {
+      DisableGPUProcess("Failed to create PUiCompositorController endpoints");
+      return nullptr;
+    }
+
+    mGPUChild->SendInitUiCompositorController(aId, std::move(parentPipe));
+    result = UiCompositorControllerChild::CreateForGPUProcess(
+        mProcessToken, std::move(childPipe), aWidget);
+
+    if (result) {
+      result->SetCompositorSurfaceManager(
+          mProcess->GetCompositorSurfaceManager());
+    }
+  }
+  return result.forget();
+}
+#endif  // defined(MOZ_WIDGET_ANDROID)
+
+void GPUProcessManager::OnProcessLaunchComplete(GPUProcessHost* aHost) {
+  MOZ_ASSERT(mProcess && mProcess == aHost);
+
+  if (!mProcess->IsConnected()) {
+    DisableGPUProcess("Failed to connect GPU process");
+    return;
+  }
+
+  mGPUChild = mProcess->GetActor();
+  mProcessToken = mProcess->GetProcessToken();
+#if defined(XP_WIN)
+  if (mAppInForeground) {
+    SetProcessIsForeground();
+  }
+#endif
+
+  ipc::Endpoint<PVsyncBridgeParent> vsyncParent;
+  ipc::Endpoint<PVsyncBridgeChild> vsyncChild;
+  nsresult rv = PVsyncBridge::CreateEndpoints(mGPUChild->OtherPid(),
+                                              base::GetCurrentProcId(),
+                                              &vsyncParent, &vsyncChild);
+  if (NS_FAILED(rv)) {
+    DisableGPUProcess("Failed to create PVsyncBridge endpoints");
+    return;
+  }
+
+  mVsyncBridge = VsyncBridgeChild::Create(mVsyncIOThread, mProcessToken,
+                                          std::move(vsyncChild));
+  mGPUChild->SendInitVsyncBridge(std::move(vsyncParent));
+
+  // Flush any pref updates that happened during launch and weren't
+  // included in the blobs set up in LaunchGPUProcess.
+  for (const mozilla::dom::Pref& pref : mQueuedPrefs) {
+    Unused << NS_WARN_IF(!mGPUChild->SendPreferenceUpdate(pref));
+  }
+  mQueuedPrefs.Clear();
+
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::GPUProcessStatus, "Running"_ns);
+
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::GPUProcessLaunchCount,
+      static_cast<int>(mTotalProcessAttempts));
+
+  ReinitializeRendering();
+}
+
+void GPUProcessManager::OnProcessDeclaredStable() { mProcessStable = true; }
+
+static bool ShouldLimitDeviceResets(uint32_t count, int32_t deltaMilliseconds) {
+  // We decide to limit by comparing the amount of resets that have happened
+  // and time since the last reset to two prefs.
+  int32_t timeLimit = StaticPrefs::gfx_device_reset_threshold_ms_AtStartup();
+  int32_t countLimit = StaticPrefs::gfx_device_reset_limit_AtStartup();
+
+  bool hasTimeLimit = timeLimit >= 0;
+  bool hasCountLimit = countLimit >= 0;
+
+  bool triggeredTime = deltaMilliseconds < timeLimit;
+  bool triggeredCount = count > (uint32_t)countLimit;
+
+  // If we have both prefs set then it needs to trigger both limits,
+  // otherwise we only test the pref that is set or none
+  if (hasTimeLimit && hasCountLimit) {
+    return triggeredTime && triggeredCount;
+  } else if (hasTimeLimit) {
+    return triggeredTime;
+  } else if (hasCountLimit) {
+    return triggeredCount;
+  }
+
+  return false;
+}
+
+void GPUProcessManager::ResetCompositors() {
+  // Note: this will recreate devices in addition to recreating compositors.
+  // This isn't optimal, but this is only used on linux where acceleration
+  // isn't enabled by default, and this way we don't need a new code path.
+  SimulateDeviceReset();
+}
+
+void GPUProcessManager::SimulateDeviceReset() {
+  // Make sure we rebuild environment and configuration for accelerated
+  // features.
+  gfxPlatform::GetPlatform()->CompositorUpdated();
+
+  if (mProcess) {
+    if (mGPUChild) {
+      mGPUChild->SendSimulateDeviceReset();
+    }
+  } else {
+    wr::RenderThread::Get()->SimulateDeviceReset();
+  }
+}
+
+bool GPUProcessManager::FallbackFromAcceleration(wr::WebRenderError aError,
+                                                 const nsCString& aMsg) {
+  if (aError == wr::WebRenderError::INITIALIZE) {
+    return gfxPlatform::FallbackFromAcceleration(
+        gfx::FeatureStatus::Unavailable, "WebRender initialization failed",
+        aMsg);
+  } else if (aError == wr::WebRenderError::MAKE_CURRENT) {
+    return gfxPlatform::FallbackFromAcceleration(
+        gfx::FeatureStatus::Unavailable,
+        "Failed to make render context current",
+        "FEATURE_FAILURE_WEBRENDER_MAKE_CURRENT"_ns);
+  } else if (aError == wr::WebRenderError::RENDER) {
+    return gfxPlatform::FallbackFromAcceleration(
+        gfx::FeatureStatus::Unavailable, "Failed to render WebRender",
+        "FEATURE_FAILURE_WEBRENDER_RENDER"_ns);
+  } else if (aError == wr::WebRenderError::NEW_SURFACE) {
+    // If we cannot create a new Surface even in the final fallback
+    // configuration then force a crash.
+    return gfxPlatform::FallbackFromAcceleration(
+        gfx::FeatureStatus::Unavailable, "Failed to create new surface",
+        "FEATURE_FAILURE_WEBRENDER_NEW_SURFACE"_ns,
+        /* aCrashAfterFinalFallback */ true);
+  } else if (aError == wr::WebRenderError::BEGIN_DRAW) {
+    return gfxPlatform::FallbackFromAcceleration(
+        gfx::FeatureStatus::Unavailable, "BeginDraw() failed",
+        "FEATURE_FAILURE_WEBRENDER_BEGIN_DRAW"_ns);
+  } else if (aError == wr::WebRenderError::EXCESSIVE_RESETS) {
+    return gfxPlatform::FallbackFromAcceleration(
+        gfx::FeatureStatus::Unavailable, "Device resets exceeded threshold",
+        "FEATURE_FAILURE_WEBRENDER_EXCESSIVE_RESETS"_ns);
+  } else {
+    MOZ_ASSERT_UNREACHABLE("Invalid value");
+    return gfxPlatform::FallbackFromAcceleration(
+        gfx::FeatureStatus::Unavailable, "Unhandled failure reason",
+        "FEATURE_FAILURE_WEBRENDER_UNHANDLED"_ns);
+  }
+}
+
+bool GPUProcessManager::DisableWebRenderConfig(wr::WebRenderError aError,
+                                               const nsCString& aMsg) {
+  // If we have a stable compositor process, this may just be due to an OOM or
+  // bad driver state. In that case, we should consider restarting the GPU
+  // process, or simulating a device reset to teardown the compositors to
+  // hopefully alleviate the situation.
+  if (IsProcessStable(TimeStamp::Now())) {
+    if (mProcess) {
+      mProcess->KillProcess();
+    } else {
+      SimulateDeviceReset();
+    }
+
+    mLastError = Some(aError);
+    mLastErrorMsg = Some(aMsg);
+    return false;
+  }
+
+  mLastError.reset();
+  mLastErrorMsg.reset();
+
+  // Disable WebRender
+  bool wantRestart = FallbackFromAcceleration(aError, aMsg);
+  gfx::gfxVars::SetUseWebRenderDCompVideoOverlayWin(false);
+
+  // If we still have the GPU process, and we fallback to a new configuration
+  // that prefers to have the GPU process, reset the counter. Because we
+  // updated the gfxVars, we want to flag the GPUChild to wait for the update
+  // to be processed before creating new compositor sessions, otherwise we risk
+  // them being out of sync with the content/parent processes.
+  if (wantRestart && mProcess && mGPUChild) {
+    mUnstableProcessAttempts = 1;
+    mGPUChild->MarkWaitForVarUpdate();
+  }
+
+  return true;
+}
+
+void GPUProcessManager::DisableWebRender(wr::WebRenderError aError,
+                                         const nsCString& aMsg) {
+  if (DisableWebRenderConfig(aError, aMsg)) {
+    if (mProcess) {
+      DestroyRemoteCompositorSessions();
+    } else {
+      DestroyInProcessCompositorSessions();
+    }
+    NotifyListenersOnCompositeDeviceReset();
+  }
+}
+
+void GPUProcessManager::NotifyWebRenderError(wr::WebRenderError aError) {
+  gfxCriticalNote << "Handling webrender error " << (unsigned int)aError;
+  if (aError == wr::WebRenderError::VIDEO_OVERLAY) {
+#ifdef XP_WIN
+    gfxVars::SetUseWebRenderDCompVideoOverlayWin(false);
+#else
+    MOZ_ASSERT_UNREACHABLE("unexpected to be called");
+#endif
+    return;
+  }
+  DisableWebRender(aError, nsCString());
+}
+
+/* static */ void GPUProcessManager::RecordDeviceReset(
+    DeviceResetReason aReason) {
+  if (aReason != DeviceResetReason::FORCED_RESET) {
+    Telemetry::Accumulate(Telemetry::DEVICE_RESET_REASON, uint32_t(aReason));
+  }
+
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::DeviceResetReason, int(aReason));
+}
+
+bool GPUProcessManager::OnDeviceReset(bool aTrackThreshold) {
+  // Ignore resets for thresholding if requested.
+  if (!aTrackThreshold) {
+    return false;
+  }
+
+  // Detect whether the device is resetting too quickly or too much
+  // indicating that we should give up and use software
+  mDeviceResetCount++;
+
+  auto newTime = TimeStamp::Now();
+  auto delta = (int32_t)(newTime - mDeviceResetLastTime).ToMilliseconds();
+  mDeviceResetLastTime = newTime;
+
+  // Returns true if we should disable acceleration due to the reset.
+  return ShouldLimitDeviceResets(mDeviceResetCount, delta);
+}
+
+void GPUProcessManager::OnInProcessDeviceReset(bool aTrackThreshold) {
+  if (OnDeviceReset(aTrackThreshold)) {
+    gfxCriticalNoteOnce << "In-process device reset threshold exceeded";
+#ifdef MOZ_WIDGET_GTK
+    // FIXME(aosmond): Should we disable WebRender on other platforms?
+    DisableWebRenderConfig(wr::WebRenderError::EXCESSIVE_RESETS, nsCString());
+#endif
+  }
+#ifdef XP_WIN
+  // Ensure device reset handling before re-creating in process sessions.
+  // Normally nsWindow::OnPaint() already handled it.
+  gfxWindowsPlatform::GetPlatform()->HandleDeviceReset();
+#endif
+  DestroyInProcessCompositorSessions();
+  NotifyListenersOnCompositeDeviceReset();
+}
+
+void GPUProcessManager::OnRemoteProcessDeviceReset(GPUProcessHost* aHost) {
+  if (OnDeviceReset(/* aTrackThreshold */ true)) {
+    DestroyProcess();
+    DisableGPUProcess("GPU processed experienced too many device resets");
+    HandleProcessLost();
+    return;
+  }
+
+  DestroyRemoteCompositorSessions();
+  NotifyListenersOnCompositeDeviceReset();
+}
+
+void GPUProcessManager::NotifyListenersOnCompositeDeviceReset() {
+  for (const auto& listener : mListeners) {
+    listener->OnCompositorDeviceReset();
+  }
+}
+
+void GPUProcessManager::OnProcessUnexpectedShutdown(GPUProcessHost* aHost) {
+  MOZ_ASSERT(mProcess && mProcess == aHost);
+
+  if (StaticPrefs::layers_gpu_process_crash_also_crashes_browser()) {
+    MOZ_CRASH("GPU process crashed and pref is set to crash the browser.");
+  }
+
+  CompositorManagerChild::OnGPUProcessLost(aHost->GetProcessToken());
+  DestroyProcess(/* aUnexpectedShutdown */ true);
+
+  if (mUnstableProcessAttempts >
+      uint32_t(StaticPrefs::layers_gpu_process_max_restarts())) {
+    char disableMessage[64];
+    SprintfLiteral(disableMessage, "GPU process disabled after %d attempts",
+                   mTotalProcessAttempts);
+    if (!MaybeDisableGPUProcess(disableMessage, /* aAllowRestart */ true)) {
+      // Fallback wants the GPU process. Reset our counter.
+      mUnstableProcessAttempts = 0;
+      HandleProcessLost();
+    }
+  } else if (mUnstableProcessAttempts >
+                 uint32_t(StaticPrefs::
+                              layers_gpu_process_max_restarts_with_decoder()) &&
+             mDecodeVideoOnGpuProcess) {
+    mDecodeVideoOnGpuProcess = false;
+    Telemetry::Accumulate(Telemetry::GPU_PROCESS_CRASH_FALLBACKS,
+                          uint32_t(FallbackType::DECODINGDISABLED));
+    HandleProcessLost();
+  } else {
+    Telemetry::Accumulate(Telemetry::GPU_PROCESS_CRASH_FALLBACKS,
+                          uint32_t(FallbackType::NONE));
+    HandleProcessLost();
+  }
+}
+
+void GPUProcessManager::HandleProcessLost() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // The shutdown and restart sequence for the GPU process is as follows:
+  //
+  //  (1) The GPU process dies. IPDL will enqueue an ActorDestroy message on
+  //      each channel owning a bridge to the GPU process, on the thread owning
+  //      that channel.
+  //
+  //  (2) The first channel to process its ActorDestroy message will post a
+  //      message to the main thread to call NotifyRemoteActorDestroyed on the
+  //      GPUProcessManager, which calls OnProcessUnexpectedShutdown if it has
+  //      not handled shutdown for this process yet. OnProcessUnexpectedShutdown
+  //      is responsible for tearing down the old process and deciding whether
+  //      or not to disable the GPU process. It then calls this function,
+  //      HandleProcessLost.
+  //
+  //  (3) We then notify each widget that its session with the compositor is now
+  //      invalid. The widget is responsible for destroying its layer manager
+  //      and CompositorBridgeChild. Note that at this stage, not all actors may
+  //      have received ActorDestroy yet. CompositorBridgeChild may attempt to
+  //      send messages, and if this happens, it will probably report a
+  //      MsgDropped error. This is okay.
+  //
+  //  (4) At this point, the UI process has a clean slate: no layers should
+  //      exist for the old compositor. We may make a decision on whether or not
+  //      to re-launch the GPU process. Or, on Android if the app is in the
+  //      background we may decide to wait until it comes to the foreground
+  //      before re-launching.
+  //
+  //  (5) When we do decide to re-launch, or continue without a GPU process, we
+  //      notify each ContentParent of the lost connection. It will request new
+  //      endpoints from the GPUProcessManager and forward them to its
+  //      ContentChild. The parent-side of these endpoints may come from the
+  //      compositor thread of the UI process, or the compositor thread of the
+  //      GPU process. However, no actual compositors should exist yet.
+  //
+  //  (6) Each ContentChild will receive new endpoints. It will destroy its
+  //      Compositor/ImageBridgeChild singletons and recreate them, as well
+  //      as invalidate all retained layers.
+  //
+  //  (7) In addition, each ContentChild will ask each of its BrowserChildren
+  //      to re-request association with the compositor for the window
+  //      owning the tab. The sequence of calls looks like:
+  //        (a) [CONTENT] ContentChild::RecvReinitRendering
+  //        (b) [CONTENT] BrowserChild::ReinitRendering
+  //        (c) [CONTENT] BrowserChild::SendEnsureLayersConnected
+  //        (d)      [UI] BrowserParent::RecvEnsureLayersConnected
+  //        (e)      [UI] RemoteLayerTreeOwner::EnsureLayersConnected
+  //        (f)      [UI] CompositorBridgeChild::SendNotifyChildRecreated
+  //
+  //      Note that at step (e), RemoteLayerTreeOwner will call
+  //      GetWindowRenderer on the nsIWidget owning the tab. This step ensures
+  //      that a compositor exists for the window. If we decided to launch a new
+  //      GPU Process, at this point we block until the process has launched and
+  //      we're able to create a new window compositor. Otherwise, if
+  //      compositing is now in-process, this will simply create a new
+  //      CompositorBridgeParent in the UI process. If there are multiple tabs
+  //      in the same window, additional tabs will simply return the already-
+  //      established compositor.
+  //
+  //      Finally, this step serves one other crucial function: tabs must be
+  //      associated with a window compositor or else they can't forward
+  //      layer transactions. So this step both ensures that a compositor
+  //      exists, and that the tab can forward layers.
+  //
+  //  (8) Last, if the window had no remote tabs, step (7) will not have
+  //      applied, and the window will not have a new compositor just yet. The
+  //      next refresh tick and paint will ensure that one exists, again via
+  //      nsIWidget::GetWindowRenderer. On Android, we called
+  //      nsIWidgetListener::RequestRepaint back in step (3) to ensure this
+  //      tick occurs, but on other platforms this is not necessary.
+
+  DestroyRemoteCompositorSessions();
+
+#ifdef MOZ_WIDGET_ANDROID
+  java::SurfaceControlManager::GetInstance()->OnGpuProcessLoss();
+#endif
+
+  // Re-launch the process if immediately if the GPU process is still enabled.
+  // Except on Android if the app is in the background, where we want to wait
+  // until the app is in the foreground again.
+  if (gfxConfig::IsEnabled(Feature::GPU_PROCESS)) {
+#ifdef MOZ_WIDGET_ANDROID
+    if (mAppInForeground) {
+#else
+    {
+#endif
+      Unused << LaunchGPUProcess();
+    }
+  } else {
+    // If the GPU process is disabled we can reinitialize rendering immediately.
+    // This will be handled in OnProcessLaunchComplete() if the GPU process is
+    // enabled.
+    ReinitializeRendering();
+  }
+}
+
+void GPUProcessManager::ReinitializeRendering() {
+  // Notify content. This will ensure that each content process re-establishes
+  // a connection to the compositor thread (whether it's in-process or in a
+  // newly launched GPU process).
+  for (const auto& listener : mListeners) {
+    listener->OnCompositorUnexpectedShutdown();
+  }
+
+  // Notify any observers that the compositor has been reinitialized,
+  // eg the ZoomConstraintsClients for parent process documents.
+  nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
+  if (observerService) {
+    observerService->NotifyObservers(nullptr, "compositor-reinitialized",
+                                     nullptr);
+  }
+}
+
+void GPUProcessManager::DestroyRemoteCompositorSessions() {
+  // Build a list of sessions to notify, since notification might delete
+  // entries from the list.
+  nsTArray<RefPtr<RemoteCompositorSession>> sessions;
+  for (auto& session : mRemoteSessions) {
+    sessions.AppendElement(session);
+  }
+
+  // Notify each widget that we have lost the GPU process. This will ensure
+  // that each widget destroys its layer manager and CompositorBridgeChild.
+  for (const auto& session : sessions) {
+    session->NotifySessionLost();
+  }
+}
+
+void GPUProcessManager::DestroyInProcessCompositorSessions() {
+  // Build a list of sessions to notify, since notification might delete
+  // entries from the list.
+  nsTArray<RefPtr<InProcessCompositorSession>> sessions;
+  for (auto& session : mInProcessSessions) {
+    sessions.AppendElement(session);
+  }
+
+  // Notify each widget that we have lost the GPU process. This will ensure
+  // that each widget destroys its layer manager and CompositorBridgeChild.
+  for (const auto& session : sessions) {
+    session->NotifySessionLost();
+  }
+
+  // Ensure our stablility state is reset so that we don't necessarily crash
+  // right away on some WebRender errors.
+  CompositorBridgeParent::ResetStable();
+  ResetProcessStable();
+}
+
+void GPUProcessManager::NotifyRemoteActorDestroyed(
+    const uint64_t& aProcessToken) {
+  if (!NS_IsMainThread()) {
+    RefPtr<Runnable> task = mTaskFactory.NewRunnableMethod(
+        &GPUProcessManager::NotifyRemoteActorDestroyed, aProcessToken);
+    NS_DispatchToMainThread(task.forget());
+    return;
+  }
+
+  if (mProcessToken != aProcessToken) {
+    // This token is for an older process; we can safely ignore it.
+    return;
+  }
+
+  // One of the bridged top-level actors for the GPU process has been
+  // prematurely terminated, and we're receiving a notification. This
+  // can happen if the ActorDestroy for a bridged protocol fires
+  // before the ActorDestroy for PGPUChild.
+  OnProcessUnexpectedShutdown(mProcess);
+}
+
+void GPUProcessManager::CleanShutdown() {
+  DestroyProcess();
+  mVsyncIOThread = nullptr;
+}
+
+void GPUProcessManager::KillProcess() {
+  if (!mProcess) {
+    return;
+  }
+
+  mProcess->KillProcess();
+}
+
+void GPUProcessManager::CrashProcess() {
+  if (!mProcess) {
+    return;
+  }
+
+  mProcess->CrashProcess();
+}
+
+void GPUProcessManager::DestroyProcess(bool aUnexpectedShutdown) {
+  if (!mProcess) {
+    return;
+  }
+
+  mProcess->Shutdown(aUnexpectedShutdown);
+  mProcessToken = 0;
+  mProcess = nullptr;
+  mGPUChild = nullptr;
+  mQueuedPrefs.Clear();
+  if (mVsyncBridge) {
+    mVsyncBridge->Close();
+    mVsyncBridge = nullptr;
+  }
+
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::GPUProcessStatus, "Destroyed"_ns);
+}
+
+already_AddRefed<CompositorSession> GPUProcessManager::CreateTopLevelCompositor(
+    nsBaseWidget* aWidget, WebRenderLayerManager* aLayerManager,
+    CSSToLayoutDeviceScale aScale, const CompositorOptions& aOptions,
+    bool aUseExternalSurfaceSize, const gfx::IntSize& aSurfaceSize,
+    uint64_t aInnerWindowId, bool* aRetryOut) {
+  MOZ_ASSERT(aRetryOut);
+
+  LayersId layerTreeId = AllocateLayerTreeId();
+
+  if (!EnsureProtocolsReady()) {
+    *aRetryOut = false;
+    return nullptr;
+  }
+
+  RefPtr<CompositorSession> session;
+
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    *aRetryOut = false;
+    return nullptr;
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    session = CreateRemoteSession(aWidget, aLayerManager, layerTreeId, aScale,
+                                  aOptions, aUseExternalSurfaceSize,
+                                  aSurfaceSize, aInnerWindowId);
+    if (!session) {
+      // We couldn't create a remote compositor, so abort the process.
+      DisableGPUProcess("Failed to create remote compositor");
+      *aRetryOut = true;
+      return nullptr;
+    }
+  } else {
+    session = InProcessCompositorSession::Create(
+        aWidget, aLayerManager, layerTreeId, aScale, aOptions,
+        aUseExternalSurfaceSize, aSurfaceSize, AllocateNamespace(),
+        aInnerWindowId);
+  }
+
+#if defined(MOZ_WIDGET_ANDROID)
+  if (session) {
+    // Nothing to do if controller gets a nullptr
+    RefPtr<UiCompositorControllerChild> controller =
+        CreateUiCompositorController(aWidget, session->RootLayerTreeId());
+    MOZ_ASSERT(controller);
+    session->SetUiCompositorControllerChild(controller);
+  }
+#endif  // defined(MOZ_WIDGET_ANDROID)
+
+  *aRetryOut = false;
+  return session.forget();
+}
+
+RefPtr<CompositorSession> GPUProcessManager::CreateRemoteSession(
+    nsBaseWidget* aWidget, WebRenderLayerManager* aLayerManager,
+    const LayersId& aRootLayerTreeId, CSSToLayoutDeviceScale aScale,
+    const CompositorOptions& aOptions, bool aUseExternalSurfaceSize,
+    const gfx::IntSize& aSurfaceSize, uint64_t aInnerWindowId) {
+#ifdef MOZ_WIDGET_SUPPORTS_OOP_COMPOSITING
+  widget::CompositorWidgetInitData initData;
+  aWidget->GetCompositorWidgetInitData(&initData);
+
+  RefPtr<CompositorBridgeChild> child =
+      CompositorManagerChild::CreateWidgetCompositorBridge(
+          mProcessToken, aLayerManager, AllocateNamespace(), aScale, aOptions,
+          aUseExternalSurfaceSize, aSurfaceSize, aInnerWindowId);
+  if (!child) {
+    gfxCriticalNote << "Failed to create CompositorBridgeChild";
+    return nullptr;
+  }
+
+  RefPtr<CompositorVsyncDispatcher> dispatcher =
+      aWidget->GetCompositorVsyncDispatcher();
+  RefPtr<widget::CompositorWidgetVsyncObserver> observer =
+      new widget::CompositorWidgetVsyncObserver(mVsyncBridge, aRootLayerTreeId);
+
+  widget::CompositorWidgetChild* widget =
+      new widget::CompositorWidgetChild(dispatcher, observer, initData);
+  if (!child->SendPCompositorWidgetConstructor(widget, initData)) {
+    return nullptr;
+  }
+  if (!widget->Initialize()) {
+    return nullptr;
+  }
+  if (!child->SendInitialize(aRootLayerTreeId)) {
+    return nullptr;
+  }
+
+  RefPtr<APZCTreeManagerChild> apz = nullptr;
+  if (aOptions.UseAPZ()) {
+    PAPZCTreeManagerChild* papz =
+        child->SendPAPZCTreeManagerConstructor(LayersId{0});
+    if (!papz) {
+      return nullptr;
+    }
+    apz = static_cast<APZCTreeManagerChild*>(papz);
+
+    ipc::Endpoint<PAPZInputBridgeParent> parentPipe;
+    ipc::Endpoint<PAPZInputBridgeChild> childPipe;
+    nsresult rv = PAPZInputBridge::CreateEndpoints(mGPUChild->OtherPid(),
+                                                   base::GetCurrentProcId(),
+                                                   &parentPipe, &childPipe);
+    if (NS_FAILED(rv)) {
+      return nullptr;
+    }
+    mGPUChild->SendInitAPZInputBridge(aRootLayerTreeId, std::move(parentPipe));
+
+    RefPtr<APZInputBridgeChild> inputBridge =
+        APZInputBridgeChild::Create(mProcessToken, std::move(childPipe));
+    if (!inputBridge) {
+      return nullptr;
+    }
+
+    apz->SetInputBridge(inputBridge);
+  }
+
+  return new RemoteCompositorSession(aWidget, child, widget, apz,
+                                     aRootLayerTreeId);
+#else
+  gfxCriticalNote << "Platform does not support out-of-process compositing";
+  return nullptr;
+#endif
+}
+
+bool GPUProcessManager::CreateContentBridges(
+    base::ProcessId aOtherProcess,
+    ipc::Endpoint<PCompositorManagerChild>* aOutCompositor,
+    ipc::Endpoint<PImageBridgeChild>* aOutImageBridge,
+    ipc::Endpoint<PVRManagerChild>* aOutVRBridge,
+    ipc::Endpoint<PRemoteDecoderManagerChild>* aOutVideoManager,
+    dom::ContentParentId aChildId, nsTArray<uint32_t>* aNamespaces) {
+  if (!CreateContentCompositorManager(aOtherProcess, aChildId,
+                                      aOutCompositor) ||
+      !CreateContentImageBridge(aOtherProcess, aChildId, aOutImageBridge) ||
+      !CreateContentVRManager(aOtherProcess, aChildId, aOutVRBridge)) {
+    return false;
+  }
+  // VideoDeocderManager is only supported in the GPU process, so we allow this
+  // to be fallible.
+  CreateContentRemoteDecoderManager(aOtherProcess, aChildId, aOutVideoManager);
+  // Allocates 3 namespaces(for CompositorManagerChild, CompositorBridgeChild
+  // and ImageBridgeChild)
+  aNamespaces->AppendElement(AllocateNamespace());
+  aNamespaces->AppendElement(AllocateNamespace());
+  aNamespaces->AppendElement(AllocateNamespace());
+  return true;
+}
+
+bool GPUProcessManager::CreateContentCompositorManager(
+    base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+    ipc::Endpoint<PCompositorManagerChild>* aOutEndpoint) {
+  ipc::Endpoint<PCompositorManagerParent> parentPipe;
+  ipc::Endpoint<PCompositorManagerChild> childPipe;
+
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return false;
+  }
+
+  base::ProcessId parentPid =
+      NS_SUCCEEDED(rv) ? mGPUChild->OtherPid() : base::GetCurrentProcId();
+
+  rv = PCompositorManager::CreateEndpoints(parentPid, aOtherProcess,
+                                           &parentPipe, &childPipe);
+  if (NS_FAILED(rv)) {
+    gfxCriticalNote << "Could not create content compositor manager: "
+                    << hexa(int(rv));
+    return false;
+  }
+
+  if (mGPUChild) {
+    mGPUChild->SendNewContentCompositorManager(std::move(parentPipe), aChildId);
+  } else if (!CompositorManagerParent::Create(std::move(parentPipe), aChildId,
+                                              /* aIsRoot */ false)) {
+    return false;
+  }
+
+  *aOutEndpoint = std::move(childPipe);
+  return true;
+}
+
+bool GPUProcessManager::CreateContentImageBridge(
+    base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+    ipc::Endpoint<PImageBridgeChild>* aOutEndpoint) {
+  if (!EnsureImageBridgeChild()) {
+    return false;
+  }
+
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return false;
+  }
+
+  base::ProcessId parentPid =
+      NS_SUCCEEDED(rv) ? mGPUChild->OtherPid() : base::GetCurrentProcId();
+
+  ipc::Endpoint<PImageBridgeParent> parentPipe;
+  ipc::Endpoint<PImageBridgeChild> childPipe;
+  rv = PImageBridge::CreateEndpoints(parentPid, aOtherProcess, &parentPipe,
+                                     &childPipe);
+  if (NS_FAILED(rv)) {
+    gfxCriticalNote << "Could not create content compositor bridge: "
+                    << hexa(int(rv));
+    return false;
+  }
+
+  if (mGPUChild) {
+    mGPUChild->SendNewContentImageBridge(std::move(parentPipe), aChildId);
+  } else {
+    if (!ImageBridgeParent::CreateForContent(std::move(parentPipe), aChildId)) {
+      return false;
+    }
+  }
+
+  *aOutEndpoint = std::move(childPipe);
+  return true;
+}
+
+base::ProcessId GPUProcessManager::GPUProcessPid() {
+  base::ProcessId gpuPid =
+      mGPUChild ? mGPUChild->OtherPid() : base::kInvalidProcessId;
+  return gpuPid;
+}
+
+bool GPUProcessManager::CreateContentVRManager(
+    base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+    ipc::Endpoint<PVRManagerChild>* aOutEndpoint) {
+  if (NS_WARN_IF(!EnsureVRManager())) {
+    return false;
+  }
+
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return false;
+  }
+
+  base::ProcessId parentPid =
+      NS_SUCCEEDED(rv) ? mGPUChild->OtherPid() : base::GetCurrentProcId();
+
+  ipc::Endpoint<PVRManagerParent> parentPipe;
+  ipc::Endpoint<PVRManagerChild> childPipe;
+  rv = PVRManager::CreateEndpoints(parentPid, aOtherProcess, &parentPipe,
+                                   &childPipe);
+  if (NS_FAILED(rv)) {
+    gfxCriticalNote << "Could not create content compositor bridge: "
+                    << hexa(int(rv));
+    return false;
+  }
+
+  if (mGPUChild) {
+    mGPUChild->SendNewContentVRManager(std::move(parentPipe), aChildId);
+  } else {
+    if (!VRManagerParent::CreateForContent(std::move(parentPipe), aChildId)) {
+      return false;
+    }
+  }
+
+  *aOutEndpoint = std::move(childPipe);
+  return true;
+}
+
+void GPUProcessManager::CreateContentRemoteDecoderManager(
+    base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+    ipc::Endpoint<PRemoteDecoderManagerChild>* aOutEndpoint) {
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return;
+  }
+
+  if (NS_FAILED(rv) || !StaticPrefs::media_gpu_process_decoder() ||
+      !mDecodeVideoOnGpuProcess) {
+    return;
+  }
+
+  ipc::Endpoint<PRemoteDecoderManagerParent> parentPipe;
+  ipc::Endpoint<PRemoteDecoderManagerChild> childPipe;
+
+  rv = PRemoteDecoderManager::CreateEndpoints(
+      mGPUChild->OtherPid(), aOtherProcess, &parentPipe, &childPipe);
+  if (NS_FAILED(rv)) {
+    gfxCriticalNote << "Could not create content video decoder: "
+                    << hexa(int(rv));
+    return;
+  }
+
+  mGPUChild->SendNewContentRemoteDecoderManager(std::move(parentPipe),
+                                                aChildId);
+
+  *aOutEndpoint = std::move(childPipe);
+}
+
+void GPUProcessManager::InitVideoBridge(
+    ipc::Endpoint<PVideoBridgeParent>&& aVideoBridge,
+    layers::VideoBridgeSource aSource) {
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return;
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    mGPUChild->SendInitVideoBridge(std::move(aVideoBridge), aSource);
+  }
+}
+
+void GPUProcessManager::MapLayerTreeId(LayersId aLayersId,
+                                       base::ProcessId aOwningId) {
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return;
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    mGPUChild->SendAddLayerTreeIdMapping(
+        LayerTreeIdMapping(aLayersId, aOwningId));
+  }
+
+  // Must do this *after* the call to EnsureGPUReady, so that if the
+  // process is launched as a result then it is initialized without this
+  // LayersId, meaning it can be successfully mapped.
+  LayerTreeOwnerTracker::Get()->Map(aLayersId, aOwningId);
+}
+
+void GPUProcessManager::UnmapLayerTreeId(LayersId aLayersId,
+                                         base::ProcessId aOwningId) {
+  nsresult rv = EnsureGPUReady();
+  if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+    return;
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    mGPUChild->SendRemoveLayerTreeIdMapping(
+        LayerTreeIdMapping(aLayersId, aOwningId));
+  } else {
+    CompositorBridgeParent::DeallocateLayerTreeId(aLayersId);
+  }
+
+  // Must do this *after* the call to EnsureGPUReady, so that if the
+  // process is launched as a result then it is initialized with this
+  // LayersId, meaning it can be successfully unmapped.
+  LayerTreeOwnerTracker::Get()->Unmap(aLayersId, aOwningId);
+}
+
+bool GPUProcessManager::IsLayerTreeIdMapped(LayersId aLayersId,
+                                            base::ProcessId aRequestingId) {
+  return LayerTreeOwnerTracker::Get()->IsMapped(aLayersId, aRequestingId);
+}
+
+LayersId GPUProcessManager::AllocateLayerTreeId() {
+  // Allocate tree id by using id namespace.
+  // By it, tree id does not conflict with external image id and
+  // async image pipeline id.
+  MOZ_ASSERT(NS_IsMainThread());
+  ++mResourceId;
+  if (mResourceId == UINT32_MAX) {
+    // Move to next id namespace.
+    mIdNamespace = AllocateNamespace();
+    mResourceId = 1;
+  }
+
+  uint64_t layerTreeId = mIdNamespace;
+  layerTreeId = (layerTreeId << 32) | mResourceId;
+  return LayersId{layerTreeId};
+}
+
+uint32_t GPUProcessManager::AllocateNamespace() {
+  MOZ_ASSERT(NS_IsMainThread());
+  return ++mNextNamespace;
+}
+
+bool GPUProcessManager::AllocateAndConnectLayerTreeId(
+    PCompositorBridgeChild* aCompositorBridge, base::ProcessId aOtherPid,
+    LayersId* aOutLayersId, CompositorOptions* aOutCompositorOptions) {
+  LayersId layersId = AllocateLayerTreeId();
+  *aOutLayersId = layersId;
+
+  if (!mGPUChild || !aCompositorBridge) {
+    // If we're not remoting to another process, or there is no compositor,
+    // then we'll send at most one message. In this case we can just keep
+    // the old behavior of making sure the mapping occurs, and maybe sending
+    // a creation notification.
+    MapLayerTreeId(layersId, aOtherPid);
+    if (!aCompositorBridge) {
+      return false;
+    }
+    return aCompositorBridge->SendNotifyChildCreated(layersId,
+                                                     aOutCompositorOptions);
+  }
+
+  // Use the combined message path.
+  LayerTreeOwnerTracker::Get()->Map(layersId, aOtherPid);
+  return aCompositorBridge->SendMapAndNotifyChildCreated(layersId, aOtherPid,
+                                                         aOutCompositorOptions);
+}
+
+void GPUProcessManager::EnsureVsyncIOThread() {
+  if (mVsyncIOThread) {
+    return;
+  }
+
+  mVsyncIOThread = new VsyncIOThreadHolder();
+  MOZ_RELEASE_ASSERT(mVsyncIOThread->Start());
+}
+
+void GPUProcessManager::ShutdownVsyncIOThread() { mVsyncIOThread = nullptr; }
+
+void GPUProcessManager::RegisterRemoteProcessSession(
+    RemoteCompositorSession* aSession) {
+  mRemoteSessions.AppendElement(aSession);
+}
+
+void GPUProcessManager::UnregisterRemoteProcessSession(
+    RemoteCompositorSession* aSession) {
+  mRemoteSessions.RemoveElement(aSession);
+}
+
+void GPUProcessManager::RegisterInProcessSession(
+    InProcessCompositorSession* aSession) {
+  mInProcessSessions.AppendElement(aSession);
+}
+
+void GPUProcessManager::UnregisterInProcessSession(
+    InProcessCompositorSession* aSession) {
+  mInProcessSessions.RemoveElement(aSession);
+}
+
+void GPUProcessManager::AddListener(GPUProcessListener* aListener) {
+  mListeners.AppendElement(aListener);
+}
+
+void GPUProcessManager::RemoveListener(GPUProcessListener* aListener) {
+  mListeners.RemoveElement(aListener);
+}
+
+bool GPUProcessManager::NotifyGpuObservers(const char* aTopic) {
+  if (NS_FAILED(EnsureGPUReady())) {
+    return false;
+  }
+  nsCString topic(aTopic);
+  mGPUChild->SendNotifyGpuObservers(topic);
+  return true;
+}
+
+class GPUMemoryReporter : public MemoryReportingProcess {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GPUMemoryReporter, override)
+
+  bool IsAlive() const override {
+    if (GPUProcessManager* gpm = GPUProcessManager::Get()) {
+      return !!gpm->GetGPUChild();
+    }
+    return false;
+  }
+
+  bool SendRequestMemoryReport(
+      const uint32_t& aGeneration, const bool& aAnonymize,
+      const bool& aMinimizeMemoryUsage,
+      const Maybe<ipc::FileDescriptor>& aDMDFile) override {
+    GPUChild* child = GetChild();
+    if (!child) {
+      return false;
+    }
+
+    return child->SendRequestMemoryReport(aGeneration, aAnonymize,
+                                          aMinimizeMemoryUsage, aDMDFile);
+  }
+
+  int32_t Pid() const override {
+    if (GPUChild* child = GetChild()) {
+      return (int32_t)child->OtherPid();
+    }
+    return 0;
+  }
+
+ private:
+  GPUChild* GetChild() const {
+    if (GPUProcessManager* gpm = GPUProcessManager::Get()) {
+      if (GPUChild* child = gpm->GetGPUChild()) {
+        return child;
+      }
+    }
+    return nullptr;
+  }
+
+ protected:
+  ~GPUMemoryReporter() = default;
+};
+
+RefPtr<MemoryReportingProcess> GPUProcessManager::GetProcessMemoryReporter() {
+  // Ensure mProcess is non-null before calling EnsureGPUReady, to avoid
+  // launching the process if it has not already been launched.
+  if (!mProcess || NS_FAILED(EnsureGPUReady())) {
+    return nullptr;
+  }
+  return new GPUMemoryReporter();
+}
+
+void GPUProcessManager::SetAppInForeground(bool aInForeground) {
+  if (mAppInForeground == aInForeground) {
+    return;
+  }
+
+  mAppInForeground = aInForeground;
+#if defined(XP_WIN)
+  SetProcessIsForeground();
+#endif
+}
+
+#if defined(XP_WIN)
+void GPUProcessManager::SetProcessIsForeground() {
+  NTSTATUS WINAPI NtSetInformationProcess(
+      IN HANDLE process_handle, IN ULONG info_class,
+      IN PVOID process_information, IN ULONG information_length);
+  constexpr unsigned int NtProcessInformationForeground = 25;
+
+  static bool alreadyInitialized = false;
+  static decltype(NtSetInformationProcess)* setInformationProcess = nullptr;
+  if (!alreadyInitialized) {
+    alreadyInitialized = true;
+    nsModuleHandle module(LoadLibrary(L"ntdll.dll"));
+    if (module) {
+      setInformationProcess =
+          (decltype(NtSetInformationProcess)*)GetProcAddress(
+              module, "NtSetInformationProcess");
+    }
+  }
+  if (MOZ_UNLIKELY(!setInformationProcess)) {
+    return;
+  }
+
+  unsigned pid = GPUProcessPid();
+  if (pid <= 0) {
+    return;
+  }
+  // Using the handle from mProcess->GetChildProcessHandle() fails;
+  // the PROCESS_SET_INFORMATION permission is probably missing.
+  nsAutoHandle processHandle(
+      ::OpenProcess(PROCESS_SET_INFORMATION, FALSE, pid));
+  if (!processHandle) {
+    return;
+  }
+
+  BOOLEAN foreground = mAppInForeground;
+  setInformationProcess(processHandle, NtProcessInformationForeground,
+                        (PVOID)&foreground, sizeof(foreground));
+}
+#endif
+
+RefPtr<PGPUChild::TestTriggerMetricsPromise>
+GPUProcessManager::TestTriggerMetrics() {
+  if (!NS_WARN_IF(!mGPUChild)) {
+    return mGPUChild->SendTestTriggerMetrics();
+  }
+
+  return PGPUChild::TestTriggerMetricsPromise::CreateAndReject(
+      ipc::ResponseRejectReason::SendError, __func__);
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/GPUProcessManager.h b/gfx/ipc/GPUProcessManager.h
new file mode 100644
index 0000000000..f92325ac70
--- /dev/null
+++ b/gfx/ipc/GPUProcessManager.h
@@ -0,0 +1,363 @@
+/* -*- 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 _include_mozilla_gfx_ipc_GPUProcessManager_h_
+#define _include_mozilla_gfx_ipc_GPUProcessManager_h_
+
+#include "base/basictypes.h"
+#include "base/process.h"
+#include "Units.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/dom/ipc/IdType.h"
+#include "mozilla/gfx/GPUProcessHost.h"
+#include "mozilla/gfx/PGPUChild.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/ipc/TaskFactory.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/webrender/WebRenderTypes.h"
+#include "nsIObserver.h"
+#include "nsThreadUtils.h"
+class nsBaseWidget;
+enum class DeviceResetReason;
+
+namespace mozilla {
+class MemoryReportingProcess;
+class PRemoteDecoderManagerChild;
+namespace layers {
+class IAPZCTreeManager;
+class CompositorOptions;
+class CompositorSession;
+class CompositorUpdateObserver;
+class PCompositorBridgeChild;
+class PCompositorManagerChild;
+class PImageBridgeChild;
+class PVideoBridgeParent;
+class RemoteCompositorSession;
+class InProcessCompositorSession;
+class UiCompositorControllerChild;
+class WebRenderLayerManager;
+}  // namespace layers
+namespace widget {
+class CompositorWidget;
+}  // namespace widget
+namespace dom {
+class ContentParent;
+class BrowserParent;
+}  // namespace dom
+namespace ipc {
+class GeckoChildProcessHost;
+}  // namespace ipc
+namespace gfx {
+
+class GPUChild;
+class GPUProcessListener;
+class PVRManagerChild;
+class VsyncBridgeChild;
+class VsyncIOThreadHolder;
+
+// The GPUProcessManager is a singleton responsible for creating GPU-bound
+// objects that may live in another process. Currently, it provides access
+// to the compositor via CompositorBridgeParent.
+class GPUProcessManager final : public GPUProcessHost::Listener {
+  friend class layers::RemoteCompositorSession;
+  friend class layers::InProcessCompositorSession;
+
+  typedef layers::CompositorOptions CompositorOptions;
+  typedef layers::CompositorSession CompositorSession;
+  typedef layers::CompositorUpdateObserver CompositorUpdateObserver;
+  typedef layers::IAPZCTreeManager IAPZCTreeManager;
+  typedef layers::WebRenderLayerManager WebRenderLayerManager;
+  typedef layers::LayersId LayersId;
+  typedef layers::PCompositorBridgeChild PCompositorBridgeChild;
+  typedef layers::PCompositorManagerChild PCompositorManagerChild;
+  typedef layers::PImageBridgeChild PImageBridgeChild;
+  typedef layers::PVideoBridgeParent PVideoBridgeParent;
+  typedef layers::RemoteCompositorSession RemoteCompositorSession;
+  typedef layers::InProcessCompositorSession InProcessCompositorSession;
+  typedef layers::UiCompositorControllerChild UiCompositorControllerChild;
+
+ public:
+  static void Initialize();
+  static void Shutdown();
+  static GPUProcessManager* Get();
+
+  ~GPUProcessManager();
+
+  // If not using a GPU process, launch a new GPU process asynchronously.
+  bool LaunchGPUProcess();
+  bool IsGPUProcessLaunching();
+
+  // Ensure that GPU-bound methods can be used. If no GPU process is being
+  // used, or one is launched and ready, this function returns immediately.
+  // Otherwise it blocks until the GPU process has finished launching.
+  // If the GPU process is enabled but has not yet been launched then this will
+  // launch the process. If that is not desired then check that return value of
+  // Process() is non-null before calling.
+  nsresult EnsureGPUReady();
+
+  already_AddRefed<CompositorSession> CreateTopLevelCompositor(
+      nsBaseWidget* aWidget, WebRenderLayerManager* aLayerManager,
+      CSSToLayoutDeviceScale aScale, const CompositorOptions& aOptions,
+      bool aUseExternalSurfaceSize, const gfx::IntSize& aSurfaceSize,
+      uint64_t aInnerWindowId, bool* aRetry);
+
+  bool CreateContentBridges(
+      base::ProcessId aOtherProcess,
+      mozilla::ipc::Endpoint<PCompositorManagerChild>* aOutCompositor,
+      mozilla::ipc::Endpoint<PImageBridgeChild>* aOutImageBridge,
+      mozilla::ipc::Endpoint<PVRManagerChild>* aOutVRBridge,
+      mozilla::ipc::Endpoint<PRemoteDecoderManagerChild>* aOutVideoManager,
+      dom::ContentParentId aChildId, nsTArray<uint32_t>* aNamespaces);
+
+  // Initialize GPU process with consuming end of PVideoBridge.
+  void InitVideoBridge(
+      mozilla::ipc::Endpoint<PVideoBridgeParent>&& aVideoBridge,
+      layers::VideoBridgeSource aSource);
+
+  // Maps the layer tree and process together so that aOwningPID is allowed
+  // to access aLayersId across process.
+  void MapLayerTreeId(LayersId aLayersId, base::ProcessId aOwningId);
+
+  // Release compositor-thread resources referred to by |aID|.
+  //
+  // Must run on the content main thread.
+  void UnmapLayerTreeId(LayersId aLayersId, base::ProcessId aOwningId);
+
+  // Checks to see if aLayersId and aRequestingPID have been mapped by
+  // MapLayerTreeId
+  bool IsLayerTreeIdMapped(LayersId aLayersId, base::ProcessId aRequestingId);
+
+  // Allocate an ID that can be used to refer to a layer tree and
+  // associated resources that live only on the compositor thread.
+  //
+  // Must run on the browser main thread.
+  LayersId AllocateLayerTreeId();
+
+  // Allocate an ID that can be used as Namespace and
+  // Must run on the browser main thread.
+  uint32_t AllocateNamespace();
+
+  // Allocate a layers ID and connect it to a compositor. If the compositor is
+  // null, the connect operation will not be performed, but an ID will still be
+  // allocated. This must be called from the browser main thread.
+  //
+  // Note that a layer tree id is always allocated, even if this returns false.
+  bool AllocateAndConnectLayerTreeId(PCompositorBridgeChild* aCompositorBridge,
+                                     base::ProcessId aOtherPid,
+                                     LayersId* aOutLayersId,
+                                     CompositorOptions* aOutCompositorOptions);
+
+  // Destroy and recreate all of the compositors
+  void ResetCompositors();
+
+  // Record the device reset in telemetry / annotate the crash report.
+  static void RecordDeviceReset(DeviceResetReason aReason);
+
+  void OnProcessLaunchComplete(GPUProcessHost* aHost) override;
+  void OnProcessUnexpectedShutdown(GPUProcessHost* aHost) override;
+  void SimulateDeviceReset();
+  void DisableWebRender(wr::WebRenderError aError, const nsCString& aMsg);
+  void NotifyWebRenderError(wr::WebRenderError aError);
+  void OnInProcessDeviceReset(bool aTrackThreshold);
+  void OnRemoteProcessDeviceReset(GPUProcessHost* aHost) override;
+  void OnProcessDeclaredStable() override;
+  void NotifyListenersOnCompositeDeviceReset();
+
+  // Notify the GPUProcessManager that a top-level PGPU protocol has been
+  // terminated. This may be called from any thread.
+  void NotifyRemoteActorDestroyed(const uint64_t& aProcessToken);
+
+  void AddListener(GPUProcessListener* aListener);
+  void RemoveListener(GPUProcessListener* aListener);
+
+  // Send a message to the GPU process observer service to broadcast. Returns
+  // true if the message was sent, false if not.
+  bool NotifyGpuObservers(const char* aTopic);
+
+  // Kills the GPU process. Used for tests and diagnostics
+  void KillProcess();
+
+  // Causes the GPU process to crash. Used for tests and diagnostics
+  void CrashProcess();
+
+  // Returns -1 if there is no GPU process, or the platform pid for it.
+  base::ProcessId GPUProcessPid();
+
+  // If a GPU process is present, create a MemoryReportingProcess object.
+  // Otherwise, return null.
+  RefPtr<MemoryReportingProcess> GetProcessMemoryReporter();
+
+  // Returns access to the PGPU protocol if a GPU process is present.
+  GPUChild* GetGPUChild() { return mGPUChild; }
+
+  // Returns whether or not a GPU process was ever launched.
+  bool AttemptedGPUProcess() const { return mTotalProcessAttempts > 0; }
+
+  // Returns the process host
+  GPUProcessHost* Process() { return mProcess; }
+
+  // Sets the value of mAppInForeground, and (on Windows) adjusts the priority
+  // of the GPU process accordingly.
+  void SetAppInForeground(bool aInForeground);
+
+  /*
+   * ** Test-only Method **
+   *
+   * Trigger GPU-process test metric instrumentation.
+   */
+  RefPtr<PGPUChild::TestTriggerMetricsPromise> TestTriggerMetrics();
+
+ private:
+  // Called from our xpcom-shutdown observer.
+  void OnXPCOMShutdown();
+  void OnPreferenceChange(const char16_t* aData);
+
+  bool CreateContentCompositorManager(
+      base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+      mozilla::ipc::Endpoint<PCompositorManagerChild>* aOutEndpoint);
+  bool CreateContentImageBridge(
+      base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+      mozilla::ipc::Endpoint<PImageBridgeChild>* aOutEndpoint);
+  bool CreateContentVRManager(
+      base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+      mozilla::ipc::Endpoint<PVRManagerChild>* aOutEndpoint);
+  void CreateContentRemoteDecoderManager(
+      base::ProcessId aOtherProcess, dom::ContentParentId aChildId,
+      mozilla::ipc::Endpoint<PRemoteDecoderManagerChild>* aOutEndPoint);
+
+  // Called from RemoteCompositorSession. We track remote sessions so we can
+  // notify their owning widgets that the session must be restarted.
+  void RegisterRemoteProcessSession(RemoteCompositorSession* aSession);
+  void UnregisterRemoteProcessSession(RemoteCompositorSession* aSession);
+
+  // Called from InProcessCompositorSession. We track in process sessino so we
+  // can notify their owning widgets that the session must be restarted
+  void RegisterInProcessSession(InProcessCompositorSession* aSession);
+  void UnregisterInProcessSession(InProcessCompositorSession* aSession);
+
+  void DestroyRemoteCompositorSessions();
+  void DestroyInProcessCompositorSessions();
+
+  // Returns true if we crossed the threshold such that we should disable
+  // acceleration.
+  bool OnDeviceReset(bool aTrackThreshold);
+
+  // Returns true if WebRender was enabled and is now disabled.
+  bool DisableWebRenderConfig(wr::WebRenderError aError, const nsCString& aMsg);
+
+  void FallbackToSoftware(const char* aMessage);
+
+ private:
+  GPUProcessManager();
+
+  // Permanently disable the GPU process and record a message why.
+  void DisableGPUProcess(const char* aMessage);
+
+  // May permanently disable the GPU process and record a message why. May
+  // return false if the fallback process decided we should retry the GPU
+  // process, but only if aAllowRestart is also true.
+  bool MaybeDisableGPUProcess(const char* aMessage, bool aAllowRestart);
+
+  bool FallbackFromAcceleration(wr::WebRenderError aError,
+                                const nsCString& aMsg);
+
+  void ResetProcessStable();
+
+  // Returns true if the composting pocess is currently considered to be stable.
+  bool IsProcessStable(const TimeStamp& aNow);
+
+  // Shutdown the GPU process.
+  void CleanShutdown();
+  // Destroy the process and clean up resources.
+  // Setting aUnexpectedShutdown = true indicates that this is being called to
+  // clean up resources in response to an unexpected shutdown having been
+  // detected.
+  void DestroyProcess(bool aUnexpectedShutdown = false);
+
+  void HandleProcessLost();
+  // Reinitialize rendering following a GPU process loss.
+  void ReinitializeRendering();
+
+  void EnsureVsyncIOThread();
+  void ShutdownVsyncIOThread();
+
+  bool EnsureProtocolsReady();
+  bool EnsureCompositorManagerChild();
+  bool EnsureImageBridgeChild();
+  bool EnsureVRManager();
+
+#if defined(XP_WIN)
+  void SetProcessIsForeground();
+#endif
+
+#if defined(MOZ_WIDGET_ANDROID)
+  already_AddRefed<UiCompositorControllerChild> CreateUiCompositorController(
+      nsBaseWidget* aWidget, const LayersId aId);
+#endif  // defined(MOZ_WIDGET_ANDROID)
+
+  RefPtr<CompositorSession> CreateRemoteSession(
+      nsBaseWidget* aWidget, WebRenderLayerManager* aLayerManager,
+      const LayersId& aRootLayerTreeId, CSSToLayoutDeviceScale aScale,
+      const CompositorOptions& aOptions, bool aUseExternalSurfaceSize,
+      const gfx::IntSize& aSurfaceSize, uint64_t aInnerWindowId);
+
+  DISALLOW_COPY_AND_ASSIGN(GPUProcessManager);
+
+  class Observer final : public nsIObserver {
+   public:
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIOBSERVER
+    explicit Observer(GPUProcessManager* aManager);
+
+   protected:
+    virtual ~Observer() = default;
+
+    GPUProcessManager* mManager;
+  };
+  friend class Observer;
+
+ private:
+  bool mDecodeVideoOnGpuProcess = true;
+
+  RefPtr<Observer> mObserver;
+  mozilla::ipc::TaskFactory<GPUProcessManager> mTaskFactory;
+  RefPtr<VsyncIOThreadHolder> mVsyncIOThread;
+  uint32_t mNextNamespace;
+  uint32_t mIdNamespace;
+  uint32_t mResourceId;
+
+  uint32_t mUnstableProcessAttempts;
+  uint32_t mTotalProcessAttempts;
+  TimeStamp mProcessAttemptLastTime;
+
+  nsTArray<RefPtr<RemoteCompositorSession>> mRemoteSessions;
+  nsTArray<RefPtr<InProcessCompositorSession>> mInProcessSessions;
+  nsTArray<GPUProcessListener*> mListeners;
+
+  uint32_t mDeviceResetCount;
+  TimeStamp mDeviceResetLastTime;
+
+  // Keeps track of whether not the application is in the foreground on android.
+  bool mAppInForeground;
+
+  // Fields that are associated with the current GPU process.
+  GPUProcessHost* mProcess;
+  uint64_t mProcessToken;
+  bool mProcessStable;
+  Maybe<wr::WebRenderError> mLastError;
+  Maybe<nsCString> mLastErrorMsg;
+  GPUChild* mGPUChild;
+  RefPtr<VsyncBridgeChild> mVsyncBridge;
+  // Collects any pref changes that occur during process launch (after
+  // the initial map is passed in command-line arguments) to be sent
+  // when the process can receive IPC messages.
+  nsTArray<mozilla::dom::Pref> mQueuedPrefs;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_GPUProcessManager_h_
diff --git a/gfx/ipc/GfxMessageUtils.h b/gfx/ipc/GfxMessageUtils.h
new file mode 100644
index 0000000000..e9b7b43e5a
--- /dev/null
+++ b/gfx/ipc/GfxMessageUtils.h
@@ -0,0 +1,1245 @@
+/* -*- 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 __GFXMESSAGEUTILS_H__
+#define __GFXMESSAGEUTILS_H__
+
+#include "FilterSupport.h"
+#include "ImageTypes.h"
+#include "RegionBuilder.h"
+#include "chrome/common/ipc_message_utils.h"
+#include "gfxFeature.h"
+#include "gfxFontUtils.h"
+#include "gfxFallback.h"
+#include "gfxPoint.h"
+#include "gfxRect.h"
+#include "gfxTelemetry.h"
+#include "gfxTypes.h"
+#include "ipc/EnumSerializer.h"
+#include "ipc/IPCMessageUtilsSpecializations.h"
+#include "mozilla/gfx/CrossProcessPaint.h"
+#include "mozilla/gfx/Matrix.h"
+#include "mozilla/gfx/ScaleFactor.h"
+#include "mozilla/gfx/ScaleFactors2D.h"
+#include "SharedFontList.h"
+#include "nsRect.h"
+#include "nsRegion.h"
+#include "mozilla/Array.h"
+#include "mozilla/ipc/IPDLParamTraits.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/ipc/ShmemMessageUtils.h"
+
+#include <stdint.h>
+
+#ifdef _MSC_VER
+#  pragma warning(disable : 4800)
+#endif
+
+namespace mozilla {
+
+typedef gfxImageFormat PixelFormat;
+
+}  // namespace mozilla
+
+namespace IPC {
+
+template <>
+struct ParamTraits<mozilla::gfx::Matrix> {
+  typedef mozilla::gfx::Matrix paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam._11);
+    WriteParam(aWriter, aParam._12);
+    WriteParam(aWriter, aParam._21);
+    WriteParam(aWriter, aParam._22);
+    WriteParam(aWriter, aParam._31);
+    WriteParam(aWriter, aParam._32);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (ReadParam(aReader, &aResult->_11) &&
+        ReadParam(aReader, &aResult->_12) &&
+        ReadParam(aReader, &aResult->_21) &&
+        ReadParam(aReader, &aResult->_22) &&
+        ReadParam(aReader, &aResult->_31) && ReadParam(aReader, &aResult->_32))
+      return true;
+
+    return false;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::Matrix4x4> {
+  typedef mozilla::gfx::Matrix4x4 paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+#define Wr(_f) WriteParam(writer, param._f)
+    Wr(_11);
+    Wr(_12);
+    Wr(_13);
+    Wr(_14);
+    Wr(_21);
+    Wr(_22);
+    Wr(_23);
+    Wr(_24);
+    Wr(_31);
+    Wr(_32);
+    Wr(_33);
+    Wr(_34);
+    Wr(_41);
+    Wr(_42);
+    Wr(_43);
+    Wr(_44);
+#undef Wr
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+#define Rd(_f) ReadParam(reader, &result->_f)
+    return (Rd(_11) && Rd(_12) && Rd(_13) && Rd(_14) && Rd(_21) && Rd(_22) &&
+            Rd(_23) && Rd(_24) && Rd(_31) && Rd(_32) && Rd(_33) && Rd(_34) &&
+            Rd(_41) && Rd(_42) && Rd(_43) && Rd(_44));
+#undef Rd
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::Matrix5x4> {
+  typedef mozilla::gfx::Matrix5x4 paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+#define Wr(_f) WriteParam(writer, param._f)
+    Wr(_11);
+    Wr(_12);
+    Wr(_13);
+    Wr(_14);
+    Wr(_21);
+    Wr(_22);
+    Wr(_23);
+    Wr(_24);
+    Wr(_31);
+    Wr(_32);
+    Wr(_33);
+    Wr(_34);
+    Wr(_41);
+    Wr(_42);
+    Wr(_43);
+    Wr(_44);
+    Wr(_51);
+    Wr(_52);
+    Wr(_53);
+    Wr(_54);
+#undef Wr
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+#define Rd(_f) ReadParam(reader, &result->_f)
+    return (Rd(_11) && Rd(_12) && Rd(_13) && Rd(_14) && Rd(_21) && Rd(_22) &&
+            Rd(_23) && Rd(_24) && Rd(_31) && Rd(_32) && Rd(_33) && Rd(_34) &&
+            Rd(_41) && Rd(_42) && Rd(_43) && Rd(_44) && Rd(_51) && Rd(_52) &&
+            Rd(_53) && Rd(_54));
+#undef Rd
+  }
+};
+
+template <>
+struct ParamTraits<gfxPoint> {
+  typedef gfxPoint paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.x.value);
+    WriteParam(aWriter, aParam.y.value);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return (ReadParam(aReader, &aResult->x.value) &&
+            ReadParam(aReader, &aResult->y.value));
+  }
+};
+
+template <>
+struct ParamTraits<gfxSize> {
+  typedef gfxSize paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.width);
+    WriteParam(aWriter, aParam.height);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (ReadParam(aReader, &aResult->width) &&
+        ReadParam(aReader, &aResult->height))
+      return true;
+
+    return false;
+  }
+};
+
+template <>
+struct ParamTraits<gfxRect> {
+  typedef gfxRect paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.X());
+    WriteParam(aWriter, aParam.Y());
+    WriteParam(aWriter, aParam.Width());
+    WriteParam(aWriter, aParam.Height());
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    auto x = aResult->X();
+    auto y = aResult->Y();
+    auto w = aResult->Width();
+    auto h = aResult->Height();
+
+    bool retVal = (ReadParam(aReader, &x) && ReadParam(aReader, &y) &&
+                   ReadParam(aReader, &w) && ReadParam(aReader, &h));
+    aResult->SetRect(x, y, w, h);
+    return retVal;
+  }
+};
+
+template <>
+struct ParamTraits<gfxContentType>
+    : public ContiguousEnumSerializer<gfxContentType, gfxContentType::COLOR,
+                                      gfxContentType::SENTINEL> {};
+
+template <>
+struct ParamTraits<gfxSurfaceType>
+    : public ContiguousEnumSerializer<gfxSurfaceType, gfxSurfaceType::Image,
+                                      gfxSurfaceType::Max> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::SamplingFilter>
+    : public ContiguousEnumSerializer<mozilla::gfx::SamplingFilter,
+                                      mozilla::gfx::SamplingFilter::GOOD,
+                                      mozilla::gfx::SamplingFilter::SENTINEL> {
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::BackendType>
+    : public ContiguousEnumSerializer<mozilla::gfx::BackendType,
+                                      mozilla::gfx::BackendType::NONE,
+                                      mozilla::gfx::BackendType::BACKEND_LAST> {
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::Feature>
+    : public ContiguousEnumSerializer<mozilla::gfx::Feature,
+                                      mozilla::gfx::Feature::HW_COMPOSITING,
+                                      mozilla::gfx::Feature::NumValues> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::Fallback>
+    : public ContiguousEnumSerializer<
+          mozilla::gfx::Fallback,
+          mozilla::gfx::Fallback::NO_CONSTANT_BUFFER_OFFSETTING,
+          mozilla::gfx::Fallback::NumValues> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::FeatureStatus>
+    : public ContiguousEnumSerializer<mozilla::gfx::FeatureStatus,
+                                      mozilla::gfx::FeatureStatus::Unused,
+                                      mozilla::gfx::FeatureStatus::LAST> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::LightType>
+    : public ContiguousEnumSerializer<mozilla::gfx::LightType,
+                                      mozilla::gfx::LightType::None,
+                                      mozilla::gfx::LightType::Max> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::ColorSpace>
+    : public ContiguousEnumSerializer<mozilla::gfx::ColorSpace,
+                                      mozilla::gfx::ColorSpace::SRGB,
+                                      mozilla::gfx::ColorSpace::Max> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::CompositionOp>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::CompositionOp, mozilla::gfx::CompositionOp::OP_OVER,
+          mozilla::gfx::CompositionOp::OP_COUNT> {};
+
+/*
+template <>
+struct ParamTraits<mozilla::PixelFormat>
+  : public EnumSerializer<mozilla::PixelFormat,
+                          SurfaceFormat::A8R8G8B8_UINT32,
+                          SurfaceFormat::UNKNOWN>
+{};
+*/
+
+template <>
+struct ParamTraits<mozilla::gfx::sRGBColor> {
+  typedef mozilla::gfx::sRGBColor paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.r);
+    WriteParam(writer, param.g);
+    WriteParam(writer, param.b);
+    WriteParam(writer, param.a);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->r) && ReadParam(reader, &result->g) &&
+            ReadParam(reader, &result->b) && ReadParam(reader, &result->a));
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::DeviceColor> {
+  typedef mozilla::gfx::DeviceColor paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.r);
+    WriteParam(writer, param.g);
+    WriteParam(writer, param.b);
+    WriteParam(writer, param.a);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->r) && ReadParam(reader, &result->g) &&
+            ReadParam(reader, &result->b) && ReadParam(reader, &result->a));
+  }
+};
+
+template <>
+struct ParamTraits<nsPoint> {
+  typedef nsPoint paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.x);
+    WriteParam(writer, param.y);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->x) && ReadParam(reader, &result->y));
+  }
+};
+
+template <>
+struct ParamTraits<nsIntPoint> {
+  typedef nsIntPoint paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.x);
+    WriteParam(writer, param.y);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->x) && ReadParam(reader, &result->y));
+  }
+};
+
+template <typename T>
+struct ParamTraits<mozilla::gfx::IntSizeTyped<T>> {
+  typedef mozilla::gfx::IntSizeTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.width);
+    WriteParam(writer, param.height);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->width) &&
+            ReadParam(reader, &result->height));
+  }
+};
+
+template <typename Region, typename Rect, typename Iter>
+struct RegionParamTraits {
+  typedef Region paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    for (auto iter = param.RectIter(); !iter.Done(); iter.Next()) {
+      const Rect& r = iter.Get();
+      MOZ_RELEASE_ASSERT(!r.IsEmpty(), "GFX: rect is empty.");
+      WriteParam(writer, r);
+    }
+    // empty rects are sentinel values because nsRegions will never
+    // contain them
+    WriteParam(writer, Rect());
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    RegionBuilder<Region> builder;
+    Rect rect;
+    while (ReadParam(reader, &rect)) {
+      if (rect.IsEmpty()) {
+        *result = builder.ToRegion();
+        return true;
+      }
+      builder.OrWith(rect);
+    }
+
+    return false;
+  }
+};
+
+template <class Units>
+struct ParamTraits<mozilla::gfx::IntRegionTyped<Units>>
+    : RegionParamTraits<
+          mozilla::gfx::IntRegionTyped<Units>,
+          mozilla::gfx::IntRectTyped<Units>,
+          typename mozilla::gfx::IntRegionTyped<Units>::RectIterator> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::IntSize> {
+  typedef mozilla::gfx::IntSize paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.width);
+    WriteParam(writer, param.height);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->width) &&
+            ReadParam(reader, &result->height));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::CoordTyped<T>> {
+  typedef mozilla::gfx::CoordTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.value);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->value));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::IntCoordTyped<T>> {
+  typedef mozilla::gfx::IntCoordTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.value);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->value));
+  }
+};
+
+template <class T, class U>
+struct ParamTraits<mozilla::gfx::ScaleFactor<T, U>> {
+  typedef mozilla::gfx::ScaleFactor<T, U> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.scale);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->scale));
+  }
+};
+
+template <class T, class U>
+struct ParamTraits<mozilla::gfx::ScaleFactors2D<T, U>> {
+  typedef mozilla::gfx::ScaleFactors2D<T, U> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.xScale);
+    WriteParam(writer, param.yScale);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->xScale) &&
+            ReadParam(reader, &result->yScale));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::PointTyped<T>> {
+  typedef mozilla::gfx::PointTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.x);
+    WriteParam(writer, param.y);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->x) && ReadParam(reader, &result->y));
+  }
+};
+
+template <class F, class T>
+struct ParamTraits<mozilla::gfx::Point3DTyped<F, T>> {
+  typedef mozilla::gfx::Point3DTyped<F, T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.x);
+    WriteParam(writer, param.y);
+    WriteParam(writer, param.z);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->x) && ReadParam(reader, &result->y) &&
+            ReadParam(reader, &result->z));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::IntPointTyped<T>> {
+  typedef mozilla::gfx::IntPointTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.x);
+    WriteParam(writer, param.y);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->x) && ReadParam(reader, &result->y));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::SizeTyped<T>> {
+  typedef mozilla::gfx::SizeTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.width);
+    WriteParam(writer, param.height);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (ReadParam(reader, &result->width) &&
+            ReadParam(reader, &result->height));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::RectTyped<T>> {
+  typedef mozilla::gfx::RectTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.X());
+    WriteParam(writer, param.Y());
+    WriteParam(writer, param.Width());
+    WriteParam(writer, param.Height());
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    auto x = result->X();
+    auto y = result->Y();
+    auto w = result->Width();
+    auto h = result->Height();
+
+    bool retVal = (ReadParam(reader, &x) && ReadParam(reader, &y) &&
+                   ReadParam(reader, &w) && ReadParam(reader, &h));
+    result->SetRect(x, y, w, h);
+    return retVal;
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::RectAbsoluteTyped<T>> {
+  typedef mozilla::gfx::RectAbsoluteTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.Left());
+    WriteParam(writer, param.Top());
+    WriteParam(writer, param.Right());
+    WriteParam(writer, param.Bottom());
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    auto l = result->Left();
+    auto t = result->Top();
+    auto r = result->Right();
+    auto b = result->Bottom();
+
+    bool retVal = (ReadParam(reader, &l) && ReadParam(reader, &t) &&
+                   ReadParam(reader, &r) && ReadParam(reader, &b));
+    result->SetBox(l, t, r, b);
+    return retVal;
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::IntRectTyped<T>> {
+  typedef mozilla::gfx::IntRectTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.X());
+    WriteParam(writer, param.Y());
+    WriteParam(writer, param.Width());
+    WriteParam(writer, param.Height());
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    auto x = result->X();
+    auto y = result->Y();
+    auto w = result->Width();
+    auto h = result->Height();
+
+    bool retVal = (ReadParam(reader, &x) && ReadParam(reader, &y) &&
+                   ReadParam(reader, &w) && ReadParam(reader, &h));
+    result->SetRect(x, y, w, h);
+    return retVal;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::Margin> {
+  typedef mozilla::gfx::Margin paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.top);
+    WriteParam(writer, param.right);
+    WriteParam(writer, param.bottom);
+    WriteParam(writer, param.left);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (
+        ReadParam(reader, &result->top) && ReadParam(reader, &result->right) &&
+        ReadParam(reader, &result->bottom) && ReadParam(reader, &result->left));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::MarginTyped<T>> {
+  typedef mozilla::gfx::MarginTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.top);
+    WriteParam(writer, param.right);
+    WriteParam(writer, param.bottom);
+    WriteParam(writer, param.left);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (
+        ReadParam(reader, &result->top) && ReadParam(reader, &result->right) &&
+        ReadParam(reader, &result->bottom) && ReadParam(reader, &result->left));
+  }
+};
+
+template <class T>
+struct ParamTraits<mozilla::gfx::IntMarginTyped<T>> {
+  typedef mozilla::gfx::IntMarginTyped<T> paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.top);
+    WriteParam(writer, param.right);
+    WriteParam(writer, param.bottom);
+    WriteParam(writer, param.left);
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    return (
+        ReadParam(reader, &result->top) && ReadParam(reader, &result->right) &&
+        ReadParam(reader, &result->bottom) && ReadParam(reader, &result->left));
+  }
+};
+
+template <>
+struct ParamTraits<nsRect> {
+  typedef nsRect paramType;
+
+  static void Write(MessageWriter* writer, const paramType& param) {
+    WriteParam(writer, param.X());
+    WriteParam(writer, param.Y());
+    WriteParam(writer, param.Width());
+    WriteParam(writer, param.Height());
+  }
+
+  static bool Read(MessageReader* reader, paramType* result) {
+    auto x = result->X();
+    auto y = result->Y();
+    auto w = result->Width();
+    auto h = result->Height();
+    bool retVal = (ReadParam(reader, &x) && ReadParam(reader, &y) &&
+                   ReadParam(reader, &w) && ReadParam(reader, &h));
+    result->SetRect(x, y, w, h);
+    return retVal;
+  }
+};
+
+template <>
+struct ParamTraits<nsRegion>
+    : RegionParamTraits<nsRegion, nsRect, nsRegion::RectIterator> {};
+
+template <>
+struct ParamTraits<GeckoProcessType>
+    : public ContiguousEnumSerializer<
+          GeckoProcessType, GeckoProcessType_Default, GeckoProcessType_End> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::SurfaceFormat>
+    : public ContiguousEnumSerializer<mozilla::gfx::SurfaceFormat,
+                                      mozilla::gfx::SurfaceFormat::B8G8R8A8,
+                                      mozilla::gfx::SurfaceFormat::UNKNOWN> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::ColorDepth>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::ColorDepth, mozilla::gfx::ColorDepth::_First,
+          mozilla::gfx::ColorDepth::_Last> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::TransferFunction>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::TransferFunction,
+          mozilla::gfx::TransferFunction::_First,
+          mozilla::gfx::TransferFunction::_Last> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::ColorRange>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::ColorRange, mozilla::gfx::ColorRange::_First,
+          mozilla::gfx::ColorRange::_Last> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::YUVColorSpace>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::YUVColorSpace, mozilla::gfx::YUVColorSpace::_First,
+          mozilla::gfx::YUVColorSpace::_Last> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::YUVRangedColorSpace>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::YUVRangedColorSpace,
+          mozilla::gfx::YUVRangedColorSpace::_First,
+          mozilla::gfx::YUVRangedColorSpace::_Last> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::ColorSpace2>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::ColorSpace2, mozilla::gfx::ColorSpace2::_First,
+          mozilla::gfx::ColorSpace2::_Last> {};
+
+template <>
+struct ParamTraits<mozilla::StereoMode>
+    : public ContiguousEnumSerializer<mozilla::StereoMode,
+                                      mozilla::StereoMode::MONO,
+                                      mozilla::StereoMode::MAX> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::ChromaSubsampling>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::gfx::ChromaSubsampling,
+          mozilla::gfx::ChromaSubsampling::_First,
+          mozilla::gfx::ChromaSubsampling::_Last> {};
+
+template <>
+struct ParamTraits<mozilla::gfx::ImplicitlyCopyableFloatArray>
+    : public ParamTraits<nsTArray<float>> {
+  typedef mozilla::gfx::ImplicitlyCopyableFloatArray paramType;
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::EmptyAttributes> {
+  typedef mozilla::gfx::EmptyAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {}
+
+  static bool Read(MessageReader* aReader, paramType* aResult) { return true; }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::MergeAttributes> {
+  typedef mozilla::gfx::MergeAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {}
+
+  static bool Read(MessageReader* aReader, paramType* aResult) { return true; }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::ToAlphaAttributes> {
+  typedef mozilla::gfx::ToAlphaAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {}
+
+  static bool Read(MessageReader* aReader, paramType* aResult) { return true; }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::TileAttributes> {
+  typedef mozilla::gfx::TileAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {}
+
+  static bool Read(MessageReader* aReader, paramType* aResult) { return true; }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::BlendAttributes> {
+  typedef mozilla::gfx::BlendAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mBlendMode);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mBlendMode);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::MorphologyAttributes> {
+  typedef mozilla::gfx::MorphologyAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mOperator);
+    WriteParam(aWriter, aParam.mRadii);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mOperator) ||
+        !ReadParam(aReader, &aResult->mRadii)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::FloodAttributes> {
+  typedef mozilla::gfx::FloodAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mColor);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mColor)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::OpacityAttributes> {
+  typedef mozilla::gfx::OpacityAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mOpacity);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mOpacity)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::OffsetAttributes> {
+  typedef mozilla::gfx::OffsetAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mValue);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mValue)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::DisplacementMapAttributes> {
+  typedef mozilla::gfx::DisplacementMapAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mScale);
+    WriteParam(aWriter, aParam.mXChannel);
+    WriteParam(aWriter, aParam.mYChannel);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mScale) ||
+        !ReadParam(aReader, &aResult->mXChannel) ||
+        !ReadParam(aReader, &aResult->mYChannel)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::TurbulenceAttributes> {
+  typedef mozilla::gfx::TurbulenceAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mOffset);
+    WriteParam(aWriter, aParam.mBaseFrequency);
+    WriteParam(aWriter, aParam.mSeed);
+    WriteParam(aWriter, aParam.mOctaves);
+    WriteParam(aWriter, aParam.mStitchable);
+    WriteParam(aWriter, aParam.mType);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mOffset) ||
+        !ReadParam(aReader, &aResult->mBaseFrequency) ||
+        !ReadParam(aReader, &aResult->mSeed) ||
+        !ReadParam(aReader, &aResult->mOctaves) ||
+        !ReadParam(aReader, &aResult->mStitchable) ||
+        !ReadParam(aReader, &aResult->mType)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::ImageAttributes> {
+  typedef mozilla::gfx::ImageAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mFilter);
+    WriteParam(aWriter, aParam.mInputIndex);
+    WriteParam(aWriter, aParam.mTransform);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mFilter) ||
+        !ReadParam(aReader, &aResult->mInputIndex) ||
+        !ReadParam(aReader, &aResult->mTransform)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::GaussianBlurAttributes> {
+  typedef mozilla::gfx::GaussianBlurAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mStdDeviation);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mStdDeviation)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::DropShadowAttributes> {
+  typedef mozilla::gfx::DropShadowAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mStdDeviation);
+    WriteParam(aWriter, aParam.mOffset);
+    WriteParam(aWriter, aParam.mColor);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mStdDeviation) ||
+        !ReadParam(aReader, &aResult->mOffset) ||
+        !ReadParam(aReader, &aResult->mColor)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::ColorMatrixAttributes> {
+  typedef mozilla::gfx::ColorMatrixAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mType);
+    WriteParam(aWriter, aParam.mValues);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mType) ||
+        !ReadParam(aReader, &aResult->mValues)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::ComponentTransferAttributes> {
+  typedef mozilla::gfx::ComponentTransferAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    for (int i = 0; i < 4; ++i) {
+      WriteParam(aWriter, aParam.mTypes[i]);
+    }
+    for (int i = 0; i < 4; ++i) {
+      WriteParam(aWriter, aParam.mValues[i]);
+    }
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    for (int i = 0; i < 4; ++i) {
+      if (!ReadParam(aReader, &aResult->mTypes[i])) {
+        return false;
+      }
+    }
+    for (int i = 0; i < 4; ++i) {
+      if (!ReadParam(aReader, &aResult->mValues[i])) {
+        return false;
+      }
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::ConvolveMatrixAttributes> {
+  typedef mozilla::gfx::ConvolveMatrixAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mKernelSize);
+    WriteParam(aWriter, aParam.mKernelMatrix);
+    WriteParam(aWriter, aParam.mDivisor);
+    WriteParam(aWriter, aParam.mBias);
+    WriteParam(aWriter, aParam.mTarget);
+    WriteParam(aWriter, aParam.mEdgeMode);
+    WriteParam(aWriter, aParam.mKernelUnitLength);
+    WriteParam(aWriter, aParam.mPreserveAlpha);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mKernelSize) ||
+        !ReadParam(aReader, &aResult->mKernelMatrix) ||
+        !ReadParam(aReader, &aResult->mDivisor) ||
+        !ReadParam(aReader, &aResult->mBias) ||
+        !ReadParam(aReader, &aResult->mTarget) ||
+        !ReadParam(aReader, &aResult->mEdgeMode) ||
+        !ReadParam(aReader, &aResult->mKernelUnitLength) ||
+        !ReadParam(aReader, &aResult->mPreserveAlpha)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::DiffuseLightingAttributes> {
+  typedef mozilla::gfx::DiffuseLightingAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mLightType);
+    WriteParam(aWriter, aParam.mLightValues);
+    WriteParam(aWriter, aParam.mSurfaceScale);
+    WriteParam(aWriter, aParam.mKernelUnitLength);
+    WriteParam(aWriter, aParam.mColor);
+    WriteParam(aWriter, aParam.mLightingConstant);
+    WriteParam(aWriter, aParam.mSpecularExponent);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mLightType) ||
+        !ReadParam(aReader, &aResult->mLightValues) ||
+        !ReadParam(aReader, &aResult->mSurfaceScale) ||
+        !ReadParam(aReader, &aResult->mKernelUnitLength) ||
+        !ReadParam(aReader, &aResult->mColor) ||
+        !ReadParam(aReader, &aResult->mLightingConstant) ||
+        !ReadParam(aReader, &aResult->mSpecularExponent)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::SpecularLightingAttributes> {
+  typedef mozilla::gfx::SpecularLightingAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mLightType);
+    WriteParam(aWriter, aParam.mLightValues);
+    WriteParam(aWriter, aParam.mSurfaceScale);
+    WriteParam(aWriter, aParam.mKernelUnitLength);
+    WriteParam(aWriter, aParam.mColor);
+    WriteParam(aWriter, aParam.mLightingConstant);
+    WriteParam(aWriter, aParam.mSpecularExponent);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mLightType) ||
+        !ReadParam(aReader, &aResult->mLightValues) ||
+        !ReadParam(aReader, &aResult->mSurfaceScale) ||
+        !ReadParam(aReader, &aResult->mKernelUnitLength) ||
+        !ReadParam(aReader, &aResult->mColor) ||
+        !ReadParam(aReader, &aResult->mLightingConstant) ||
+        !ReadParam(aReader, &aResult->mSpecularExponent)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::CompositeAttributes> {
+  typedef mozilla::gfx::CompositeAttributes paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mOperator);
+    WriteParam(aWriter, aParam.mCoefficients);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mOperator) ||
+        !ReadParam(aReader, &aResult->mCoefficients)) {
+      return false;
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::gfx::Glyph> {
+  typedef mozilla::gfx::Glyph paramType;
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mIndex);
+    WriteParam(aWriter, aParam.mPosition);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return (ReadParam(aReader, &aResult->mIndex) &&
+            ReadParam(aReader, &aResult->mPosition));
+  }
+};
+
+template <typename T, size_t Length>
+struct ParamTraits<mozilla::Array<T, Length>> {
+  typedef mozilla::Array<T, Length> paramType;
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    for (size_t i = 0; i < Length; i++) {
+      WriteParam(aWriter, aParam[i]);
+    }
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    for (size_t i = 0; i < Length; i++) {
+      if (!ReadParam<T>(aReader, &aResult->operator[](i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::SideBits>
+    : public BitFlagsEnumSerializer<mozilla::SideBits,
+                                    mozilla::SideBits::eAll> {};
+
+template <>
+struct ParamTraits<gfxSparseBitSet> {
+  typedef gfxSparseBitSet paramType;
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mBlockIndex);
+    WriteParam(aWriter, aParam.mBlocks);
+  }
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mBlockIndex) &&
+           ReadParam(aReader, &aResult->mBlocks);
+  }
+};
+
+template <>
+struct ParamTraits<gfxSparseBitSet::Block> {
+  typedef gfxSparseBitSet::Block paramType;
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    aWriter->WriteBytes(&aParam, sizeof(aParam));
+  }
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return aReader->ReadBytesInto(aResult, sizeof(*aResult));
+  }
+};
+
+// The actual FontVisibility enum is defined in gfxTypes.h
+template <>
+struct ParamTraits<FontVisibility>
+    : public ContiguousEnumSerializer<FontVisibility, FontVisibility::Unknown,
+                                      FontVisibility::Count> {};
+
+template <>
+struct ParamTraits<mozilla::fontlist::Pointer> {
+  typedef mozilla::fontlist::Pointer paramType;
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    uint32_t v = aParam.mBlockAndOffset;
+    WriteParam(aWriter, v);
+  }
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    uint32_t v;
+    if (ReadParam(aReader, &v)) {
+      aResult->mBlockAndOffset.store(v);
+      return true;
+    }
+    return false;
+  }
+};
+
+}  // namespace IPC
+
+namespace mozilla {
+namespace ipc {
+
+template <>
+struct IPDLParamTraits<gfx::PaintFragment> {
+  typedef mozilla::gfx::PaintFragment paramType;
+  static void Write(IPC::MessageWriter* aWriter, IProtocol* aActor,
+                    paramType&& aParam) {
+    Shmem shmem;
+    if (aParam.mSize.IsEmpty() ||
+        !aActor->AllocShmem(aParam.mRecording.mLen, &shmem)) {
+      WriteParam(aWriter, gfx::IntSize(0, 0));
+      return;
+    }
+
+    memcpy(shmem.get<uint8_t>(), aParam.mRecording.mData,
+           aParam.mRecording.mLen);
+
+    WriteParam(aWriter, aParam.mSize);
+    WriteIPDLParam(aWriter, aActor, std::move(shmem));
+    WriteParam(aWriter, aParam.mDependencies);
+  }
+
+  static bool Read(IPC::MessageReader* aReader, IProtocol* aActor,
+                   paramType* aResult) {
+    if (!ReadParam(aReader, &aResult->mSize)) {
+      return false;
+    }
+    if (aResult->mSize.IsEmpty()) {
+      return true;
+    }
+    Shmem shmem;
+    if (!ReadIPDLParam(aReader, aActor, &shmem) ||
+        !ReadParam(aReader, &aResult->mDependencies)) {
+      aActor->DeallocShmem(shmem);
+      return false;
+    }
+
+    if (!aResult->mRecording.Allocate(shmem.Size<uint8_t>())) {
+      aResult->mSize.SizeTo(0, 0);
+      aActor->DeallocShmem(shmem);
+      return true;
+    }
+
+    memcpy(aResult->mRecording.mData, shmem.get<uint8_t>(),
+           shmem.Size<uint8_t>());
+    aActor->DeallocShmem(shmem);
+    return true;
+  }
+};
+
+}  // namespace ipc
+}  // namespace mozilla
+
+#endif /* __GFXMESSAGEUTILS_H__ */
diff --git a/gfx/ipc/GraphicsMessages.ipdlh b/gfx/ipc/GraphicsMessages.ipdlh
new file mode 100644
index 0000000000..6f201c9272
--- /dev/null
+++ b/gfx/ipc/GraphicsMessages.ipdlh
@@ -0,0 +1,92 @@
+/* -*- 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 "mozilla/GfxMessageUtils.h";
+
+using struct DxgiAdapterDesc from "mozilla/D3DMessageUtils.h";
+using struct mozilla::null_t from "mozilla/ipc/IPCCore.h";
+using mozilla::gfx::FeatureStatus from "gfxTelemetry.h";
+using mozilla::gfx::BackendType from "mozilla/gfx/Types.h";
+using mozilla::gfx::IntSize from "mozilla/gfx/Point.h";
+using gfxImageFormat from "mozilla/gfx/Types.h";
+using mozilla::gfx::D3D11Checks::VideoFormatOption from "mozilla/gfx/D3D11Checks.h";
+using mozilla::gfx::D3D11Checks::VideoFormatOptionSet from "mozilla/gfx/D3D11Checks.h";
+
+namespace mozilla {
+namespace gfx {
+
+struct D3D11DeviceStatus
+{
+  bool isWARP;
+  bool textureSharingWorks;
+  uint32_t featureLevel;
+  DxgiAdapterDesc adapter;
+  int32_t sequenceNumber;
+  VideoFormatOptionSet formatOptions;
+};
+
+struct DevicePrefs
+{
+  FeatureStatus hwCompositing;
+  FeatureStatus d3d11Compositing;
+  FeatureStatus oglCompositing;
+  FeatureStatus useD2D1;
+  FeatureStatus d3d11HwAngle;
+};
+
+struct ContentDeviceData
+{
+  DevicePrefs prefs;
+  D3D11DeviceStatus d3d11;
+  uint8_t[] cmsOutputProfileData;
+};
+
+// Represents the state of a feature that has failed to initialize.
+struct FeatureFailure
+{
+  FeatureStatus status;
+  nsCString message;
+  nsCString failureId;
+};
+
+struct GPUDeviceData
+{
+  // If a feature state has changed from Enabled -> Failure, these will be non-
+  // null.
+  FeatureFailure? d3d11Compositing;
+  FeatureFailure? oglCompositing;
+  D3D11DeviceStatus? gpuDevice;
+};
+
+union GfxVarValue
+{
+  BackendType;
+  bool;
+  gfxImageFormat;
+  IntSize;
+  nsCString;
+  nsString;
+  int32_t;
+  float;
+  uint64_t[];
+};
+
+struct GfxVarUpdate
+{
+  uint32_t index;
+  GfxVarValue value;
+};
+
+struct GfxInfoFeatureStatus
+{
+    int32_t feature;
+    int32_t status;
+    nsCString failureId;
+};
+
+} // namespace gfx
+} // namespace mozilla
diff --git a/gfx/ipc/InProcessCompositorSession.cpp b/gfx/ipc/InProcessCompositorSession.cpp
new file mode 100644
index 0000000000..f5f94461cb
--- /dev/null
+++ b/gfx/ipc/InProcessCompositorSession.cpp
@@ -0,0 +1,105 @@
+/* -*- 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 "InProcessCompositorSession.h"
+
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorManagerChild.h"
+#include "mozilla/layers/CompositorManagerParent.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "mozilla/widget/CompositorWidget.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsBaseWidget.h"
+
+namespace mozilla {
+namespace layers {
+
+InProcessCompositorSession::InProcessCompositorSession(
+    nsBaseWidget* aWidget, widget::CompositorWidget* aCompositorWidget,
+    CompositorBridgeChild* aChild, CompositorBridgeParent* aParent)
+    : CompositorSession(aWidget, aCompositorWidget->AsDelegate(), aChild,
+                        aParent->RootLayerTreeId()),
+      mCompositorBridgeParent(aParent),
+      mCompositorWidget(aCompositorWidget) {
+  gfx::GPUProcessManager::Get()->RegisterInProcessSession(this);
+}
+
+/* static */
+RefPtr<InProcessCompositorSession> InProcessCompositorSession::Create(
+    nsBaseWidget* aWidget, WebRenderLayerManager* aLayerManager,
+    const LayersId& aRootLayerTreeId, CSSToLayoutDeviceScale aScale,
+    const CompositorOptions& aOptions, bool aUseExternalSurfaceSize,
+    const gfx::IntSize& aSurfaceSize, uint32_t aNamespace,
+    uint64_t aInnerWindowId) {
+  widget::CompositorWidgetInitData initData;
+  aWidget->GetCompositorWidgetInitData(&initData);
+
+  RefPtr<CompositorWidget> widget =
+      CompositorWidget::CreateLocal(initData, aOptions, aWidget);
+  RefPtr<CompositorBridgeParent> parent =
+      CompositorManagerParent::CreateSameProcessWidgetCompositorBridge(
+          aScale, aOptions, aUseExternalSurfaceSize, aSurfaceSize,
+          aInnerWindowId);
+  MOZ_ASSERT(parent);
+  parent->InitSameProcess(widget, aRootLayerTreeId);
+
+  RefPtr<CompositorBridgeChild> child =
+      CompositorManagerChild::CreateSameProcessWidgetCompositorBridge(
+          aLayerManager, aNamespace);
+  MOZ_ASSERT(child);
+  if (!child) {
+    gfxCriticalNote << "Failed to create CompositorBridgeChild";
+    return nullptr;
+  }
+
+  return new InProcessCompositorSession(aWidget, widget, child, parent);
+}
+
+void InProcessCompositorSession::NotifySessionLost() {
+  mWidget->NotifyCompositorSessionLost(this);
+}
+
+CompositorBridgeParent* InProcessCompositorSession::GetInProcessBridge() const {
+  return mCompositorBridgeParent;
+}
+
+void InProcessCompositorSession::SetContentController(
+    GeckoContentController* aController) {
+  mCompositorBridgeParent->SetControllerForLayerTree(mRootLayerTreeId,
+                                                     aController);
+}
+
+RefPtr<IAPZCTreeManager> InProcessCompositorSession::GetAPZCTreeManager()
+    const {
+  return mCompositorBridgeParent->GetAPZCTreeManager(mRootLayerTreeId);
+}
+
+nsIWidget* InProcessCompositorSession::GetWidget() const { return mWidget; }
+
+void InProcessCompositorSession::Shutdown() {
+  // Destroy will synchronously wait for the parent to acknowledge shutdown,
+  // at which point CBP will defer a Release on the compositor thread. We
+  // can safely release our reference now, and let the destructor run on either
+  // thread.
+#if defined(MOZ_WIDGET_ANDROID)
+  if (mUiCompositorControllerChild) {
+    mUiCompositorControllerChild->Destroy();
+    mUiCompositorControllerChild = nullptr;
+  }
+#endif  // defined(MOZ_WIDGET_ANDROID)
+  if (mCompositorBridgeChild) {
+    mCompositorBridgeChild->Destroy();
+    mCompositorBridgeChild = nullptr;
+  }
+  mCompositorBridgeParent = nullptr;
+  mCompositorWidget = nullptr;
+  gfx::GPUProcessManager::Get()->UnregisterInProcessSession(this);
+}
+
+}  // namespace layers
+}  // namespace mozilla
diff --git a/gfx/ipc/InProcessCompositorSession.h b/gfx/ipc/InProcessCompositorSession.h
new file mode 100644
index 0000000000..e9a346253a
--- /dev/null
+++ b/gfx/ipc/InProcessCompositorSession.h
@@ -0,0 +1,54 @@
+/* -*- 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 _include_mozilla_gfx_ipc_InProcessCompositorSession_h_
+#define _include_mozilla_gfx_ipc_InProcessCompositorSession_h_
+
+#include "CompositorSession.h"
+#include "mozilla/gfx/Point.h"
+#include "Units.h"
+
+class nsIWidget;
+
+namespace mozilla {
+namespace layers {
+
+class CompositorOptions;
+class WebRenderLayerManager;
+
+// A CompositorSession where both the child and parent CompositorBridge reside
+// in the same process.
+class InProcessCompositorSession final : public CompositorSession {
+ public:
+  static RefPtr<InProcessCompositorSession> Create(
+      nsBaseWidget* baseWidget, WebRenderLayerManager* aLayerManager,
+      const LayersId& aRootLayerTreeId, CSSToLayoutDeviceScale aScale,
+      const CompositorOptions& aOptions, bool aUseExternalSurfaceSize,
+      const gfx::IntSize& aSurfaceSize, uint32_t aNamespace,
+      uint64_t aInnerWindowId);
+
+  CompositorBridgeParent* GetInProcessBridge() const override;
+  void SetContentController(GeckoContentController* aController) override;
+  nsIWidget* GetWidget() const;
+  RefPtr<IAPZCTreeManager> GetAPZCTreeManager() const override;
+  void Shutdown() override;
+
+  void NotifySessionLost();
+
+ private:
+  InProcessCompositorSession(nsBaseWidget* aWidget,
+                             widget::CompositorWidget* aCompositorWidget,
+                             CompositorBridgeChild* aChild,
+                             CompositorBridgeParent* aParent);
+
+ private:
+  RefPtr<CompositorBridgeParent> mCompositorBridgeParent;
+  RefPtr<CompositorWidget> mCompositorWidget;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_InProcessCompositorSession_h_
diff --git a/gfx/ipc/OverlayInfo.h b/gfx/ipc/OverlayInfo.h
new file mode 100644
index 0000000000..3137e2ef98
--- /dev/null
+++ b/gfx/ipc/OverlayInfo.h
@@ -0,0 +1,53 @@
+/* -*- 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 _include_mozilla_gfx_ipc_OverlayInfo_h_
+#define _include_mozilla_gfx_ipc_OverlayInfo_h_
+
+namespace IPC {
+template <typename>
+struct ParamTraits;
+}  // namespace IPC
+
+namespace mozilla {
+namespace layers {
+
+enum class OverlaySupportType : uint8_t {
+  None,
+  Software,
+  Direct,
+  Scaling,
+  MAX  // sentinel for the count of all effect types
+};
+
+struct OverlayInfo {
+  // This constructor needed for IPDL purposes, don't use it anywhere else.
+  OverlayInfo() = default;
+
+  bool mSupportsOverlays = false;
+  OverlaySupportType mNv12Overlay = OverlaySupportType::None;
+  OverlaySupportType mYuy2Overlay = OverlaySupportType::None;
+  OverlaySupportType mBgra8Overlay = OverlaySupportType::None;
+  OverlaySupportType mRgb10a2Overlay = OverlaySupportType::None;
+
+  friend struct IPC::ParamTraits<OverlayInfo>;
+};
+
+struct SwapChainInfo {
+  // This constructor needed for IPDL purposes, don't use it anywhere else.
+  SwapChainInfo() = default;
+
+  explicit SwapChainInfo(bool aTearingSupported)
+      : mTearingSupported(aTearingSupported) {}
+
+  bool mTearingSupported = false;
+
+  friend struct IPC::ParamTraits<SwapChainInfo>;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // _include_mozilla_gfx_ipc_OverlayInfo_h_
diff --git a/gfx/ipc/PCanvasManager.ipdl b/gfx/ipc/PCanvasManager.ipdl
new file mode 100644
index 0000000000..9a75a2b2b0
--- /dev/null
+++ b/gfx/ipc/PCanvasManager.ipdl
@@ -0,0 +1,48 @@
+/* -*- 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 "mozilla/layers/LayersMessageUtils.h";
+include protocol PWebGL;
+include protocol PWebGPU;
+
+using mozilla::layers::RemoteTextureOwnerId from "mozilla/layers/LayersTypes.h";
+using mozilla::webgl::FrontBufferSnapshotIpc from "mozilla/dom/WebGLIpdl.h";
+
+namespace mozilla {
+namespace gfx {
+
+/**
+ * The PCanvasManager protocol is the top-level protocol between the main and
+ * worker threads in the content process, and the renderer thread in the
+ * compositor process. This protocol should be used to create accelerated
+ * canvas instances.
+ */
+[NeedsOtherPid]
+sync protocol PCanvasManager
+{
+  manages PWebGL;
+  manages PWebGPU;
+
+parent:
+  // Actor that represents one WebGL context.
+  async PWebGL();
+
+  // Actor that represents one WebGPU context.
+  async PWebGPU();
+
+  // Set the local manager ID for the canvas manager.
+  async Initialize(uint32_t aManagerId);
+
+  // Get the front buffer pixels for the given manager/protocol. This is
+  // intended to be used by the main thread in the content process to block
+  // reading without having to block on the worker thread that owns the context
+  // instance.
+  sync GetSnapshot(uint32_t aManagerId, int32_t aProtocolId, RemoteTextureOwnerId? ownerId) returns (FrontBufferSnapshotIpc ret);
+};
+
+} // gfx
+} // mozilla
diff --git a/gfx/ipc/PGPU.ipdl b/gfx/ipc/PGPU.ipdl
new file mode 100644
index 0000000000..89bf585fee
--- /dev/null
+++ b/gfx/ipc/PGPU.ipdl
@@ -0,0 +1,190 @@
+/* -*- 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 GraphicsMessages;
+include MemoryReportTypes;
+include HangTypes;
+include PrefsTypes;
+include protocol PAPZInputBridge;
+include protocol PCompositorManager;
+include protocol PImageBridge;
+include protocol PProfiler;
+include protocol PVRGPU;
+include protocol PVRManager;
+include protocol PVideoBridge;
+include protocol PVsyncBridge;
+include protocol PUiCompositorController;
+include protocol PRemoteDecoderManager;
+
+#if defined(MOZ_SANDBOX) && defined(MOZ_DEBUG) && defined(ENABLE_TESTS)
+include protocol PSandboxTesting;
+#endif
+
+include "mozilla/ipc/ByteBufUtils.h";
+include "mozilla/layers/LayersMessageUtils.h";
+
+using base::ProcessId from "base/process.h";
+using mozilla::dom::ContentParentId from "mozilla/dom/ipc/IdType.h";
+using mozilla::dom::NativeThreadId from "mozilla/dom/NativeThreadId.h";
+using mozilla::Telemetry::HistogramAccumulation from "mozilla/TelemetryComms.h";
+using mozilla::Telemetry::KeyedHistogramAccumulation from "mozilla/TelemetryComms.h";
+using mozilla::Telemetry::ScalarAction from "mozilla/TelemetryComms.h";
+using mozilla::Telemetry::KeyedScalarAction from "mozilla/TelemetryComms.h";
+using mozilla::Telemetry::ChildEventData from "mozilla/TelemetryComms.h";
+using mozilla::Telemetry::DiscardedData from "mozilla/TelemetryComms.h";
+using mozilla::gfx::Feature from "gfxFeature.h";
+using mozilla::gfx::Fallback from "gfxFallback.h";
+using mozilla::layers::LayersId from "mozilla/layers/LayersTypes.h";
+using mozilla::layers::OverlayInfo from "mozilla/layers/OverlayInfo.h";
+using mozilla::layers::SwapChainInfo from "mozilla/layers/OverlayInfo.h";
+using mozilla::media::MediaCodecsSupported from "MediaCodecsSupport.h";
+using mozilla::layers::VideoBridgeSource from "mozilla/layers/VideoBridgeUtils.h";
+
+namespace mozilla {
+namespace gfx {
+
+struct LayerTreeIdMapping {
+  LayersId layersId;
+  ProcessId ownerId;
+};
+
+// This protocol allows the UI process to talk to the GPU process. There is one
+// instance of this protocol, with the GPUParent living on the main thread of
+// the GPU process and the GPUChild living on the main thread of the UI process.
+[NeedsOtherPid]
+sync protocol PGPU
+{
+parent:
+  // Sent by the UI process to initiate core settings.
+  async Init(GfxVarUpdate[] vars,
+             DevicePrefs devicePrefs,
+             LayerTreeIdMapping[] mapping,
+             GfxInfoFeatureStatus[] features,
+             uint32_t wrNamespace);
+
+  async InitCompositorManager(Endpoint<PCompositorManagerParent> endpoint);
+  async InitVsyncBridge(Endpoint<PVsyncBridgeParent> endpoint);
+  async InitImageBridge(Endpoint<PImageBridgeParent> endpoint);
+  async InitVideoBridge(Endpoint<PVideoBridgeParent> endpoint, VideoBridgeSource aSource);
+  async InitVRManager(Endpoint<PVRManagerParent> endpoint);
+  async InitUiCompositorController(LayersId rootLayerTreeId, Endpoint<PUiCompositorControllerParent> endpoint);
+  async InitAPZInputBridge(LayersId layersId,
+                           Endpoint<PAPZInputBridgeParent> endpoint);
+  async InitProfiler(Endpoint<PProfilerChild> endpoint);
+  // Forward GPU process its endpoints to the VR process.
+  async InitVR(Endpoint<PVRGPUChild> endpoint);
+  // Called to update a gfx variable.
+  async UpdateVar(GfxVarUpdate var);
+
+  async PreferenceUpdate(Pref pref);
+
+  // Create a new content-process compositor bridge.
+  async NewContentCompositorManager(Endpoint<PCompositorManagerParent> endpoint, ContentParentId childId);
+  async NewContentImageBridge(Endpoint<PImageBridgeParent> endpoint, ContentParentId childId);
+  async NewContentVRManager(Endpoint<PVRManagerParent> endpoint, ContentParentId childId);
+  async NewContentRemoteDecoderManager(Endpoint<PRemoteDecoderManagerParent> endpoint, ContentParentId childId);
+
+  // Called to notify the GPU process of who owns a layersId.
+  sync AddLayerTreeIdMapping(LayerTreeIdMapping mapping);
+  async RemoveLayerTreeIdMapping(LayerTreeIdMapping mapping);
+
+  // Request the current DeviceStatus from the GPU process. This blocks until
+  // one is available (i.e., Init has completed).
+  sync GetDeviceStatus() returns (GPUDeviceData status);
+
+  // Request to simulate device reset and to get the updated DeviceStatus from
+  // the GPU process. This blocks until one is available (i.e., Init has completed).
+  async SimulateDeviceReset();
+
+  // Have a message be broadcasted to the GPU process by the GPU process
+  // observer service.
+  async NotifyGpuObservers(nsCString aTopic);
+
+  async RequestMemoryReport(uint32_t generation,
+                            bool anonymize,
+                            bool minimizeMemoryUsage,
+                            FileDescriptor? DMDFile)
+      returns (uint32_t aGeneration);
+
+  async ShutdownVR();
+
+  // Functions supporting PerfStats data collection.
+  async UpdatePerfStatsCollectionMask(uint64_t aMask);
+  async CollectPerfStatsJSON() returns (nsCString aStats);
+
+#if defined(MOZ_SANDBOX) && defined(MOZ_DEBUG) && defined(ENABLE_TESTS)
+  async InitSandboxTesting(Endpoint<PSandboxTestingChild> aEndpoint);
+#endif
+
+  // Tells the gpu process to flush any pending telemetry.
+  // Used in tests and ping assembly. Buffer contains bincoded Rust structs.
+  // https://firefox-source-docs.mozilla.org/toolkit/components/glean/dev/ipc.html
+  async FlushFOGData() returns (ByteBuf buf);
+
+  // Test-only method.
+  // Asks the gpu process to trigger test-only instrumentation.
+  // The unused returned value is to have a promise we can await.
+  async TestTriggerMetrics() returns (bool unused);
+
+  // Causes the GPU process to crash. Used for tests and diagnostics.
+  async CrashProcess();
+
+child:
+  // Sent when the GPU process has initialized devices. This occurs once, after
+  // Init().
+  async InitComplete(GPUDeviceData data);
+
+  // Sent when APZ detects checkerboarding and apz checkerboard reporting is enabled.
+  async ReportCheckerboard(uint32_t severity, nsCString log);
+
+  // Graphics errors, analogous to PContent::GraphicsError
+  async GraphicsError(nsCString aError);
+
+  async InitCrashReporter(NativeThreadId threadId);
+
+  async CreateVRProcess();
+  async ShutdownVRProcess();
+
+  // Have a message be broadcasted to the UI process by the UI process
+  // observer service.
+  async NotifyUiObservers(nsCString aTopic);
+
+  // Messages for reporting telemetry to the UI process.
+  async AccumulateChildHistograms(HistogramAccumulation[] accumulations);
+  async AccumulateChildKeyedHistograms(KeyedHistogramAccumulation[] accumulations);
+  async UpdateChildScalars(ScalarAction[] actions);
+  async UpdateChildKeyedScalars(KeyedScalarAction[] actions);
+  async RecordChildEvents(ChildEventData[] events);
+  async RecordDiscardedData(DiscardedData data);
+
+  async DeclareStable();
+  async NotifyDeviceReset(GPUDeviceData status);
+  async NotifyOverlayInfo(OverlayInfo info);
+  async NotifySwapChainInfo(SwapChainInfo info);
+  async FlushMemory(nsString reason);
+
+  async AddMemoryReport(MemoryReport aReport);
+
+  // Update the UI process after a feature's status has changed. This is used
+  // outside of the normal startup flow.
+  async UpdateFeature(Feature aFeature, FeatureFailure aChange);
+
+  // Notify about:support/Telemetry that a fallback occurred.
+  async UsedFallback(Fallback aFallback, nsCString message);
+
+  async BHRThreadHang(HangDetails aDetails);
+
+  // Update the cached list of codec supported following a check in the
+  // GPU parent.
+  async UpdateMediaCodecsSupported(MediaCodecsSupported aSupported);
+
+  // Sent from time-to-time to limit the amount of telemetry vulnerable to loss
+  // Buffer contains bincoded Rust structs.
+  // https://firefox-source-docs.mozilla.org/toolkit/components/glean/dev/ipc.html
+  async FOGData(ByteBuf buf);
+};
+
+} // namespace gfx
+} // namespace mozilla
diff --git a/gfx/ipc/PVsyncBridge.ipdl b/gfx/ipc/PVsyncBridge.ipdl
new file mode 100644
index 0000000000..b498d8a0af
--- /dev/null
+++ b/gfx/ipc/PVsyncBridge.ipdl
@@ -0,0 +1,27 @@
+/* -*- 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 "mozilla/layers/LayersMessageUtils.h";
+
+using class mozilla::TimeStamp from "mozilla/TimeStamp.h";
+using mozilla::layers::LayersId from "mozilla/layers/LayersTypes.h";
+using mozilla::VsyncEvent from "mozilla/VsyncDispatcher.h";
+
+namespace mozilla {
+namespace gfx {
+
+// This protocol only serves one purpose: deliver vsync notifications from a
+// dedicated thread in the UI process to the compositor thread in the
+// compositor process. The child side exists in the UI process, and the
+// parent side in the GPU process.
+[NeedsOtherPid]
+sync protocol PVsyncBridge
+{
+parent:
+  async NotifyVsync(VsyncEvent vsync, LayersId layersId);
+};
+
+} // namespace gfx
+} // namespace mozilla
diff --git a/gfx/ipc/RemoteCompositorSession.cpp b/gfx/ipc/RemoteCompositorSession.cpp
new file mode 100644
index 0000000000..bbd8ddd13f
--- /dev/null
+++ b/gfx/ipc/RemoteCompositorSession.cpp
@@ -0,0 +1,98 @@
+/* -*- 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 "RemoteCompositorSession.h"
+#include "gfxPlatform.h"
+#include "mozilla/VsyncDispatcher.h"
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/layers/APZChild.h"
+#include "mozilla/layers/APZCTreeManagerChild.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/GeckoContentController.h"
+#include "mozilla/Unused.h"
+#include "nsBaseWidget.h"
+#if defined(MOZ_WIDGET_ANDROID)
+#  include "mozilla/layers/UiCompositorControllerChild.h"
+#endif  // defined(MOZ_WIDGET_ANDROID)
+
+namespace mozilla {
+namespace layers {
+
+using namespace gfx;
+using namespace widget;
+
+RemoteCompositorSession::RemoteCompositorSession(
+    nsBaseWidget* aWidget, CompositorBridgeChild* aChild,
+    CompositorWidgetDelegate* aWidgetDelegate, APZCTreeManagerChild* aAPZ,
+    const LayersId& aRootLayerTreeId)
+    : CompositorSession(aWidget, aWidgetDelegate, aChild, aRootLayerTreeId),
+      mAPZ(aAPZ) {
+  MOZ_ASSERT(!gfxPlatform::IsHeadless());
+  GPUProcessManager::Get()->RegisterRemoteProcessSession(this);
+  if (mAPZ) {
+    mAPZ->SetCompositorSession(this);
+  }
+}
+
+RemoteCompositorSession::~RemoteCompositorSession() {
+  // This should have been shutdown first.
+  MOZ_ASSERT(!mCompositorBridgeChild);
+#if defined(MOZ_WIDGET_ANDROID)
+  MOZ_ASSERT(!mUiCompositorControllerChild);
+#endif  // defined(MOZ_WIDGET_ANDROID)
+}
+
+void RemoteCompositorSession::NotifySessionLost() {
+  // Re-entrancy should be impossible: when we are being notified of a lost
+  // session, we have by definition not shut down yet. We will shutdown, but
+  // then will be removed from the notification list.
+  mWidget->NotifyCompositorSessionLost(this);
+}
+
+CompositorBridgeParent* RemoteCompositorSession::GetInProcessBridge() const {
+  return nullptr;
+}
+
+void RemoteCompositorSession::SetContentController(
+    GeckoContentController* aController) {
+  mContentController = aController;
+  mCompositorBridgeChild->SendPAPZConstructor(new APZChild(aController),
+                                              LayersId{0});
+}
+
+GeckoContentController* RemoteCompositorSession::GetContentController() {
+  return mContentController.get();
+}
+
+nsIWidget* RemoteCompositorSession::GetWidget() const { return mWidget; }
+
+RefPtr<IAPZCTreeManager> RemoteCompositorSession::GetAPZCTreeManager() const {
+  return mAPZ;
+}
+
+void RemoteCompositorSession::Shutdown() {
+  mContentController = nullptr;
+  if (mAPZ) {
+    mAPZ->SetCompositorSession(nullptr);
+    mAPZ->Destroy();
+  }
+  if (mCompositorBridgeChild) {
+    mCompositorBridgeChild->Destroy();
+    mCompositorBridgeChild = nullptr;
+  }
+  mCompositorWidgetDelegate = nullptr;
+  mWidget = nullptr;
+#if defined(MOZ_WIDGET_ANDROID)
+  if (mUiCompositorControllerChild) {
+    mUiCompositorControllerChild->Destroy();
+    mUiCompositorControllerChild = nullptr;
+  }
+#endif  // defined(MOZ_WIDGET_ANDROID)
+  GPUProcessManager::Get()->UnregisterRemoteProcessSession(this);
+}
+
+}  // namespace layers
+}  // namespace mozilla
diff --git a/gfx/ipc/RemoteCompositorSession.h b/gfx/ipc/RemoteCompositorSession.h
new file mode 100644
index 0000000000..d55d56e07a
--- /dev/null
+++ b/gfx/ipc/RemoteCompositorSession.h
@@ -0,0 +1,45 @@
+/* -*- 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 include_mozilla_gfx_ipc_RemoteCompositorSession_h
+#define include_mozilla_gfx_ipc_RemoteCompositorSession_h
+
+#include "CompositorSession.h"
+#include "mozilla/gfx/Point.h"
+#include "Units.h"
+
+class nsIWidget;
+
+namespace mozilla {
+namespace layers {
+
+class APZCTreeManagerChild;
+
+class RemoteCompositorSession final : public CompositorSession {
+ public:
+  RemoteCompositorSession(nsBaseWidget* aWidget, CompositorBridgeChild* aChild,
+                          CompositorWidgetDelegate* aWidgetDelegate,
+                          APZCTreeManagerChild* aAPZ,
+                          const LayersId& aRootLayerTreeId);
+  virtual ~RemoteCompositorSession();
+
+  CompositorBridgeParent* GetInProcessBridge() const override;
+  void SetContentController(GeckoContentController* aController) override;
+  GeckoContentController* GetContentController();
+  nsIWidget* GetWidget() const;
+  RefPtr<IAPZCTreeManager> GetAPZCTreeManager() const override;
+  void Shutdown() override;
+
+  void NotifySessionLost();
+
+ private:
+  RefPtr<APZCTreeManagerChild> mAPZ;
+  RefPtr<GeckoContentController> mContentController;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // include_mozilla_gfx_ipc_RemoteCompositorSession_h
diff --git a/gfx/ipc/VsyncBridgeChild.cpp b/gfx/ipc/VsyncBridgeChild.cpp
new file mode 100644
index 0000000000..044a24f320
--- /dev/null
+++ b/gfx/ipc/VsyncBridgeChild.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 "VsyncBridgeChild.h"
+#include "VsyncIOThreadHolder.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/ipc/Endpoint.h"
+
+namespace mozilla {
+namespace gfx {
+
+VsyncBridgeChild::VsyncBridgeChild(RefPtr<VsyncIOThreadHolder> aThread,
+                                   const uint64_t& aProcessToken)
+    : mThread(aThread), mProcessToken(aProcessToken) {}
+
+VsyncBridgeChild::~VsyncBridgeChild() = default;
+
+/* static */
+RefPtr<VsyncBridgeChild> VsyncBridgeChild::Create(
+    RefPtr<VsyncIOThreadHolder> aThread, const uint64_t& aProcessToken,
+    Endpoint<PVsyncBridgeChild>&& aEndpoint) {
+  RefPtr<VsyncBridgeChild> child = new VsyncBridgeChild(aThread, aProcessToken);
+
+  RefPtr<nsIRunnable> task = NewRunnableMethod<Endpoint<PVsyncBridgeChild>&&>(
+      "gfx::VsyncBridgeChild::Open", child, &VsyncBridgeChild::Open,
+      std::move(aEndpoint));
+  aThread->GetThread()->Dispatch(task.forget(), nsIThread::DISPATCH_NORMAL);
+
+  return child;
+}
+
+void VsyncBridgeChild::Open(Endpoint<PVsyncBridgeChild>&& aEndpoint) {
+  if (!aEndpoint.Bind(this)) {
+    // The GPU Process Manager might be gone if we receive ActorDestroy very
+    // late in shutdown.
+    if (GPUProcessManager* gpm = GPUProcessManager::Get())
+      gpm->NotifyRemoteActorDestroyed(mProcessToken);
+    return;
+  }
+}
+
+class NotifyVsyncTask : public Runnable {
+ public:
+  NotifyVsyncTask(RefPtr<VsyncBridgeChild> aVsyncBridge,
+                  const VsyncEvent& aVsync, const layers::LayersId& aLayersId)
+      : Runnable("gfx::NotifyVsyncTask"),
+        mVsyncBridge(aVsyncBridge),
+        mVsync(aVsync),
+        mLayersId(aLayersId) {}
+
+  NS_IMETHOD Run() override {
+    mVsyncBridge->NotifyVsyncImpl(mVsync, mLayersId);
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<VsyncBridgeChild> mVsyncBridge;
+  VsyncEvent mVsync;
+  layers::LayersId mLayersId;
+};
+
+bool VsyncBridgeChild::IsOnVsyncIOThread() const {
+  return mThread->IsOnCurrentThread();
+}
+
+void VsyncBridgeChild::NotifyVsync(const VsyncEvent& aVsync,
+                                   const layers::LayersId& aLayersId) {
+  // This should be on the Vsync thread (not the Vsync I/O thread).
+  MOZ_ASSERT(!IsOnVsyncIOThread());
+
+  RefPtr<NotifyVsyncTask> task = new NotifyVsyncTask(this, aVsync, aLayersId);
+  mThread->Dispatch(task.forget());
+}
+
+void VsyncBridgeChild::NotifyVsyncImpl(const VsyncEvent& aVsync,
+                                       const layers::LayersId& aLayersId) {
+  // This should be on the Vsync I/O thread.
+  MOZ_ASSERT(IsOnVsyncIOThread());
+
+  if (!mProcessToken) {
+    return;
+  }
+  SendNotifyVsync(aVsync, aLayersId);
+}
+
+void VsyncBridgeChild::Close() {
+  if (!IsOnVsyncIOThread()) {
+    mThread->Dispatch(NewRunnableMethod("gfx::VsyncBridgeChild::Close", this,
+                                        &VsyncBridgeChild::Close));
+    return;
+  }
+
+  // We clear mProcessToken when the channel is closed.
+  if (!mProcessToken) {
+    return;
+  }
+
+  // Clear the process token so we don't notify the GPUProcessManager. It
+  // already knows we're closed since it manually called Close, and in fact the
+  // GPM could have already been destroyed during shutdown.
+  mProcessToken = 0;
+
+  // Close the underlying IPC channel.
+  PVsyncBridgeChild::Close();
+}
+
+void VsyncBridgeChild::ActorDestroy(ActorDestroyReason aWhy) {
+  if (mProcessToken) {
+    GPUProcessManager::Get()->NotifyRemoteActorDestroyed(mProcessToken);
+    mProcessToken = 0;
+  }
+}
+
+void VsyncBridgeChild::ProcessingError(Result aCode, const char* aReason) {
+  MOZ_RELEASE_ASSERT(aCode == MsgDropped,
+                     "Processing error in VsyncBridgeChild");
+}
+
+void VsyncBridgeChild::HandleFatalError(const char* aMsg) {
+  dom::ContentChild::FatalErrorIfNotUsingGPUProcess(aMsg, OtherPid());
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/VsyncBridgeChild.h b/gfx/ipc/VsyncBridgeChild.h
new file mode 100644
index 0000000000..a0727ce5fe
--- /dev/null
+++ b/gfx/ipc/VsyncBridgeChild.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 include_gfx_ipc_VsyncBridgeChild_h
+#define include_gfx_ipc_VsyncBridgeChild_h
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/gfx/PVsyncBridgeChild.h"
+
+namespace mozilla {
+namespace gfx {
+
+class VsyncIOThreadHolder;
+
+class VsyncBridgeChild final : public PVsyncBridgeChild {
+  friend class NotifyVsyncTask;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VsyncBridgeChild, final)
+
+  static RefPtr<VsyncBridgeChild> Create(
+      RefPtr<VsyncIOThreadHolder> aThread, const uint64_t& aProcessToken,
+      Endpoint<PVsyncBridgeChild>&& aEndpoint);
+
+  void Close();
+
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+  void ProcessingError(Result aCode, const char* aReason) override;
+
+  void NotifyVsync(const VsyncEvent& aVsync, const layers::LayersId& aLayersId);
+
+  void HandleFatalError(const char* aMsg) override;
+
+ private:
+  VsyncBridgeChild(RefPtr<VsyncIOThreadHolder>, const uint64_t& aProcessToken);
+  virtual ~VsyncBridgeChild();
+
+  void Open(Endpoint<PVsyncBridgeChild>&& aEndpoint);
+
+  void NotifyVsyncImpl(const VsyncEvent& aVsync,
+                       const layers::LayersId& aLayersId);
+
+  bool IsOnVsyncIOThread() const;
+
+ private:
+  RefPtr<VsyncIOThreadHolder> mThread;
+  uint64_t mProcessToken;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // include_gfx_ipc_VsyncBridgeChild_h
diff --git a/gfx/ipc/VsyncBridgeParent.cpp b/gfx/ipc/VsyncBridgeParent.cpp
new file mode 100644
index 0000000000..c98b641ba2
--- /dev/null
+++ b/gfx/ipc/VsyncBridgeParent.cpp
@@ -0,0 +1,74 @@
+/* -*- 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 "VsyncBridgeParent.h"
+#include "mozilla/ipc/Endpoint.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorThread.h"
+
+using mozilla::layers::CompositorBridgeParent;
+using mozilla::layers::CompositorThreadHolder;
+
+namespace mozilla {
+namespace gfx {
+
+RefPtr<VsyncBridgeParent> VsyncBridgeParent::Start(
+    Endpoint<PVsyncBridgeParent>&& aEndpoint) {
+  RefPtr<VsyncBridgeParent> parent = new VsyncBridgeParent();
+
+  RefPtr<Runnable> task = NewRunnableMethod<Endpoint<PVsyncBridgeParent>&&>(
+      "gfx::VsyncBridgeParent::Open", parent, &VsyncBridgeParent::Open,
+      std::move(aEndpoint));
+  layers::CompositorThread()->Dispatch(task.forget());
+
+  return parent;
+}
+
+VsyncBridgeParent::VsyncBridgeParent() : mOpen(false) {
+  MOZ_COUNT_CTOR(VsyncBridgeParent);
+  mCompositorThreadRef = CompositorThreadHolder::GetSingleton();
+}
+
+VsyncBridgeParent::~VsyncBridgeParent() { MOZ_COUNT_DTOR(VsyncBridgeParent); }
+
+void VsyncBridgeParent::Open(Endpoint<PVsyncBridgeParent>&& aEndpoint) {
+  if (!aEndpoint.Bind(this)) {
+    // We can't recover from this.
+    MOZ_CRASH("Failed to bind VsyncBridgeParent to endpoint");
+  }
+  mOpen = true;
+}
+
+mozilla::ipc::IPCResult VsyncBridgeParent::RecvNotifyVsync(
+    const VsyncEvent& aVsync, const LayersId& aLayersId) {
+  CompositorBridgeParent::NotifyVsync(aVsync, aLayersId);
+  return IPC_OK();
+}
+
+void VsyncBridgeParent::Shutdown() {
+  if (!CompositorThreadHolder::IsInCompositorThread()) {
+    layers::CompositorThread()->Dispatch(
+        NewRunnableMethod("gfx::VsyncBridgeParent::ShutdownImpl", this,
+                          &VsyncBridgeParent::ShutdownImpl));
+    return;
+  }
+
+  ShutdownImpl();
+}
+
+void VsyncBridgeParent::ShutdownImpl() {
+  if (mOpen) {
+    Close();
+    mOpen = false;
+  }
+}
+
+void VsyncBridgeParent::ActorDestroy(ActorDestroyReason aWhy) {
+  mOpen = false;
+  mCompositorThreadRef = nullptr;
+}
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/VsyncBridgeParent.h b/gfx/ipc/VsyncBridgeParent.h
new file mode 100644
index 0000000000..1d1c5c7ef3
--- /dev/null
+++ b/gfx/ipc/VsyncBridgeParent.h
@@ -0,0 +1,47 @@
+/* -*- 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 include_gfx_ipc_VsyncBridgeParent_h
+#define include_gfx_ipc_VsyncBridgeParent_h
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/gfx/PVsyncBridgeParent.h"
+
+namespace mozilla {
+namespace layers {
+class CompositorThreadHolder;
+}  // namespace layers
+
+namespace gfx {
+
+class VsyncBridgeParent final : public PVsyncBridgeParent {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VsyncBridgeParent, final)
+
+  static RefPtr<VsyncBridgeParent> Start(
+      Endpoint<PVsyncBridgeParent>&& aEndpoint);
+
+  mozilla::ipc::IPCResult RecvNotifyVsync(const VsyncEvent& aVsync,
+                                          const LayersId& aLayersId);
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+
+  void Shutdown();
+
+ private:
+  VsyncBridgeParent();
+  ~VsyncBridgeParent();
+
+  void Open(Endpoint<PVsyncBridgeParent>&& aEndpoint);
+  void ShutdownImpl();
+
+ private:
+  bool mOpen;
+  RefPtr<layers::CompositorThreadHolder> mCompositorThreadRef;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // include_gfx_ipc_VsyncBridgeParent_h
diff --git a/gfx/ipc/VsyncIOThreadHolder.cpp b/gfx/ipc/VsyncIOThreadHolder.cpp
new file mode 100644
index 0000000000..51e25cc853
--- /dev/null
+++ b/gfx/ipc/VsyncIOThreadHolder.cpp
@@ -0,0 +1,50 @@
+/* -*- 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 "VsyncIOThreadHolder.h"
+
+#include "mozilla/SchedulerGroup.h"
+
+namespace mozilla {
+namespace gfx {
+
+VsyncIOThreadHolder::VsyncIOThreadHolder() {
+  MOZ_COUNT_CTOR(VsyncIOThreadHolder);
+}
+
+VsyncIOThreadHolder::~VsyncIOThreadHolder() {
+  MOZ_COUNT_DTOR(VsyncIOThreadHolder);
+
+  if (!mThread) {
+    return;
+  }
+
+  if (NS_IsMainThread()) {
+    mThread->AsyncShutdown();
+  } else {
+    SchedulerGroup::Dispatch(
+        TaskCategory::Other,
+        NewRunnableMethod("nsIThread::AsyncShutdown", mThread,
+                          &nsIThread::AsyncShutdown));
+  }
+}
+
+bool VsyncIOThreadHolder::Start() {
+  /* "VsyncIOThread" is used as the thread we send/recv IPC messages on.  We
+   * don't use the "WindowsVsyncThread" directly because it isn't servicing an
+   * nsThread event loop which is needed for IPC to return results/notify us
+   * about shutdown etc.
+   *
+   * It would be better if we could notify the IPC IO thread directly to avoid
+   * the extra ping-ponging but that doesn't seem possible. */
+  nsresult rv = NS_NewNamedThread("VsyncIOThread", getter_AddRefs(mThread));
+  return NS_SUCCEEDED(rv);
+}
+
+RefPtr<nsIThread> VsyncIOThreadHolder::GetThread() const { return mThread; }
+
+}  // namespace gfx
+}  // namespace mozilla
diff --git a/gfx/ipc/VsyncIOThreadHolder.h b/gfx/ipc/VsyncIOThreadHolder.h
new file mode 100644
index 0000000000..8158834cab
--- /dev/null
+++ b/gfx/ipc/VsyncIOThreadHolder.h
@@ -0,0 +1,43 @@
+/* -*- 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_ipc_VsyncIOThreadHolder_h
+#define mozilla_gfx_ipc_VsyncIOThreadHolder_h
+
+#include "mozilla/RefPtr.h"
+#include "nsIThread.h"
+#include "nsThreadUtils.h"
+
+namespace mozilla {
+namespace gfx {
+
+class VsyncIOThreadHolder final {
+ public:
+  VsyncIOThreadHolder();
+
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VsyncIOThreadHolder)
+
+  bool Start();
+
+  RefPtr<nsIThread> GetThread() const;
+
+  bool IsOnCurrentThread() const { return mThread->IsOnCurrentThread(); }
+
+  void Dispatch(already_AddRefed<nsIRunnable> task) {
+    mThread->Dispatch(std::move(task), NS_DISPATCH_NORMAL);
+  }
+
+ private:
+  ~VsyncIOThreadHolder();
+
+ private:
+  RefPtr<nsIThread> mThread;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_ipc_VsyncIOThreadHolder_h
diff --git a/gfx/ipc/moz.build b/gfx/ipc/moz.build
new file mode 100644
index 0000000000..ab8fb34fcd
--- /dev/null
+++ b/gfx/ipc/moz.build
@@ -0,0 +1,90 @@
+# -*- 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/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+EXPORTS.mozilla += ["D3DMessageUtils.h", "GfxMessageUtils.h"]
+
+EXPORTS.mozilla.gfx += [
+    "CanvasManagerChild.h",
+    "CanvasManagerParent.h",
+    "CanvasRenderThread.h",
+    "CrossProcessPaint.h",
+    "GPUChild.h",
+    "GPUParent.h",
+    "GPUProcessHost.h",
+    "GPUProcessImpl.h",
+    "GPUProcessListener.h",
+    "GPUProcessManager.h",
+    "VsyncBridgeChild.h",
+    "VsyncBridgeParent.h",
+    "VsyncIOThreadHolder.h",
+]
+
+EXPORTS.mozilla.layers += [
+    "CompositorOptions.h",
+    "CompositorSession.h",
+    "InProcessCompositorSession.h",
+    "OverlayInfo.h",
+    "RemoteCompositorSession.h",
+]
+
+EXPORTS.mozilla.widget += [
+    "CompositorWidgetVsyncObserver.h",
+]
+
+UNIFIED_SOURCES += [
+    "CanvasManagerChild.cpp",
+    "CanvasManagerParent.cpp",
+    "CanvasRenderThread.cpp",
+    "CompositorSession.cpp",
+    "CompositorWidgetVsyncObserver.cpp",
+    "CrossProcessPaint.cpp",
+    "D3DMessageUtils.cpp",
+    "GPUChild.cpp",
+    "GPUProcessHost.cpp",
+    "GPUProcessImpl.cpp",
+    "GPUProcessManager.cpp",
+    "InProcessCompositorSession.cpp",
+    "RemoteCompositorSession.cpp",
+    "VsyncBridgeChild.cpp",
+    "VsyncBridgeParent.cpp",
+    "VsyncIOThreadHolder.cpp",
+]
+
+SOURCES += [
+    "GPUParent.cpp",
+]
+
+IPDL_SOURCES = [
+    "GraphicsMessages.ipdlh",
+    "PCanvasManager.ipdl",
+    "PVsyncBridge.ipdl",
+]
+
+PREPROCESSED_IPDL_SOURCES += [
+    "PGPU.ipdl",
+]
+
+LOCAL_INCLUDES += [
+    "/dom/ipc",
+    "/gfx/cairo/cairo/src",
+    "/ipc/glue",
+    "/toolkit/crashreporter",
+    "/xpcom/threads",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
+    CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+
+CXXFLAGS += ["-Werror=switch"]
+
+LOCAL_INCLUDES += CONFIG["SKIA_INCLUDES"]