Bug 1855742 - Part 3. Allow recording based canvases with OffscreenCanvas. r=gfx-reviewers,lsalzman

It is disabled in this patch via the gfx.canvas.remote.allow-offscreen
pref. A follow up patch will enable this by default.

Differential Revision: https://phabricator.services.mozilla.com/D189532

dom/canvas/CanvasRenderingContext2D.cpp

@@ -118,6 +118,7 @@
 #include "mozilla/dom/SVGImageElement.h"
 #include "mozilla/dom/TextMetrics.h"
 #include "mozilla/FloatingPoint.h"
+#include "mozilla/Logging.h"
 #include "nsGlobalWindowInner.h"
 #include "nsDeviceContext.h"
 #include "nsFontMetrics.h"
@@ -1684,15 +1685,27 @@ bool CanvasRenderingContext2D::TryAcceleratedTarget(
     return false;
   }
 
-  if (!mCanvasElement) {
-    return false;
+  if (mCanvasElement) {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    WindowRenderer* renderer = WindowRendererFromCanvasElement(mCanvasElement);
+    if (NS_WARN_IF(!renderer)) {
+      return false;
+    }
+
+    aOutProvider = PersistentBufferProviderAccelerated::Create(
+        GetSize(), GetSurfaceFormat(), renderer->AsKnowsCompositor());
+  } else if (mOffscreenCanvas &&
+             StaticPrefs::gfx_canvas_remote_allow_offscreen()) {
+    RefPtr<ImageBridgeChild> imageBridge = ImageBridgeChild::GetSingleton();
+    if (NS_WARN_IF(!imageBridge)) {
+      return false;
+    }
+
+    aOutProvider = PersistentBufferProviderAccelerated::Create(
+        GetSize(), GetSurfaceFormat(), imageBridge);
   }
-  WindowRenderer* renderer = WindowRendererFromCanvasElement(mCanvasElement);
-  if (!renderer) {
-    return false;
-  }
-  aOutProvider = PersistentBufferProviderAccelerated::Create(
-      GetSize(), GetSurfaceFormat(), renderer->AsKnowsCompositor());
+
   if (!aOutProvider) {
     return false;
   }
@@ -1716,8 +1729,10 @@ bool CanvasRenderingContext2D::TrySharedTarget(
   }
 
   if (mCanvasElement) {
+    MOZ_ASSERT(NS_IsMainThread());
+
     WindowRenderer* renderer = WindowRendererFromCanvasElement(mCanvasElement);
-    if (!renderer) {
+    if (NS_WARN_IF(!renderer)) {
       return false;
     }
 
@@ -1735,7 +1750,7 @@ bool CanvasRenderingContext2D::TrySharedTarget(
       return false;
     }
 
-    aOutProvider = layers::PersistentBufferProviderShared::Create(
+    aOutProvider = PersistentBufferProviderShared::Create(
         GetSize(), GetSurfaceFormat(), imageBridge,
         !mAllowAcceleration || GetEffectiveWillReadFrequently(),
         mOffscreenCanvas->GetWindowID());

dom/canvas/OffscreenCanvasDisplayHelper.cpp

@@ -38,11 +38,25 @@ void OffscreenCanvasDisplayHelper::DestroyElement() {
   MOZ_ASSERT(NS_IsMainThread());
 
   MutexAutoLock lock(mMutex);
+  if (mImageContainer) {
+    mImageContainer->ClearAllImages();
+    mImageContainer = nullptr;
+  }
+  mFrontBufferSurface = nullptr;
   mCanvasElement = nullptr;
 }
 
 void OffscreenCanvasDisplayHelper::DestroyCanvas() {
+  if (auto* cm = gfx::CanvasManagerChild::Get()) {
+    cm->EndCanvasTransaction();
+  }
+
   MutexAutoLock lock(mMutex);
+  if (mImageContainer) {
+    mImageContainer->ClearAllImages();
+    mImageContainer = nullptr;
+  }
+  mFrontBufferSurface = nullptr;
   mOffscreenCanvas = nullptr;
   mWorkerRef = nullptr;
 }
@@ -141,6 +155,12 @@ bool OffscreenCanvasDisplayHelper::CommitFrameToCompositor(
     nsICanvasRenderingContextInternal* aContext,
     layers::TextureType aTextureType,
     const Maybe<OffscreenCanvasDisplayData>& aData) {
+  auto endTransaction = MakeScopeExit([&]() {
+    if (auto* cm = gfx::CanvasManagerChild::Get()) {
+      cm->EndCanvasTransaction();
+    }
+  });
+
   MutexAutoLock lock(mMutex);
 
   gfx::SurfaceFormat format = gfx::SurfaceFormat::B8G8R8A8;

gfx/layers/ipc/CanvasTranslator.cpp

@@ -13,6 +13,7 @@
 #include "mozilla/gfx/DrawTargetWebgl.h"
 #include "mozilla/gfx/gfxVars.h"
 #include "mozilla/gfx/GPUParent.h"
+#include "mozilla/gfx/GPUProcessManager.h"
 #include "mozilla/gfx/Logging.h"
 #include "mozilla/ipc/Endpoint.h"
 #include "mozilla/layers/BufferTexture.h"
@@ -728,9 +729,15 @@ bool CanvasTranslator::CheckForFreshCanvasDevice(int aLineNumber) {
     NotifyDeviceChanged();
   }
 
-  RefPtr<Runnable> runnable = NS_NewRunnableFunction(
-      "CanvasTranslator NotifyDeviceReset",
-      []() { gfx::GPUParent::GetSingleton()->NotifyDeviceReset(); });
+  RefPtr<Runnable> runnable =
+      NS_NewRunnableFunction("CanvasTranslator NotifyDeviceReset", []() {
+        if (XRE_IsGPUProcess()) {
+          gfx::GPUParent::GetSingleton()->NotifyDeviceReset();
+        } else {
+          gfx::GPUProcessManager::Get()->OnInProcessDeviceReset(
+              /* aTrackThreshold */ false);
+        }
+      });
 
   // It is safe to wait here because only the Compositor thread waits on us and
   // the main thread doesn't wait on the compositor thread in the GPU process.

modules/libpref/init/StaticPrefList.yaml

@@ -5693,6 +5693,12 @@
   value: false
   mirror: once
 
+# Whether OffscreenCanvas can use remote canvas
+- name: gfx.canvas.remote.allow-offscreen
+  type: RelaxedAtomicBool
+  value: false
+  mirror: always
+
 # How many worker threads spawned for remote canvas
 #  -1 - Calculate based on processor cores
 #   0 - No worker threads spawned, will do work on CanvasRenderThread