Ensures dereference of |video_frame_compositor_context_provider_| on proper thread.

This CL makes sure that the |video_frame_compositor_context_provider_|
and references to it get dereferenced to the thread it is bound to (in
this case, the |video_frame_compositor_task_runner_|

Bug: 898989
Change-Id: I98654bb5a6b29a43a384ce0308b4b97d575903a0
Reviewed-on: https://chromium-review.googlesource.com/c/1303178
Commit-Queue: CJ DiMeglio <lethalantidote@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605878}

content/renderer/media/media_factory.cc

@@ -230,6 +230,10 @@ std::unique_ptr<blink::WebVideoFrameSubmitter> MediaFactory::CreateSubmitter(
             ? render_thread->compositor_task_runner()
             : render_frame_->GetTaskRunner(
                   blink::TaskType::kInternalMediaRealTime);
+
+    // TODO(https://crbug/901513): Remove once kOnDemand is removed.
+    render_thread->SetVideoFrameCompositorTaskRunner(
+        *video_frame_compositor_task_runner);
   }
 
   std::unique_ptr<blink::WebVideoFrameSubmitter> submitter;

content/renderer/render_thread_impl.cc

@@ -1001,6 +1001,14 @@ void RenderThreadImpl::Init() {
 
 RenderThreadImpl::~RenderThreadImpl() {
   g_main_task_runner.Get() = nullptr;
+
+  // Need to make sure this reference is removed on the correct task runner;
+  if (video_frame_compositor_task_runner_ &&
+      video_frame_compositor_context_provider_) {
+    video_frame_compositor_context_provider_->AddRef();
+    video_frame_compositor_task_runner_->ReleaseSoon(
+        FROM_HERE, std::move(video_frame_compositor_context_provider_).get());
+  }
 }
 
 void RenderThreadImpl::Shutdown() {
@@ -1367,12 +1375,21 @@ media::GpuVideoAcceleratorFactories* RenderThreadImpl::GetGpuFactories() {
 scoped_refptr<viz::ContextProvider>
 RenderThreadImpl::GetVideoFrameCompositorContextProvider(
     scoped_refptr<viz::ContextProvider> unwanted_context_provider) {
+  DCHECK(video_frame_compositor_task_runner_);
   if (video_frame_compositor_context_provider_ &&
       video_frame_compositor_context_provider_ != unwanted_context_provider) {
     return video_frame_compositor_context_provider_;
   }
 
-  video_frame_compositor_context_provider_ = nullptr;
+  // Need to make sure these references are removed on the correct task runner;
+  if (video_frame_compositor_context_provider_) {
+    video_frame_compositor_context_provider_->AddRef();
+    viz::ContextProvider* context_provider_ptr =
+        video_frame_compositor_context_provider_.get();
+    video_frame_compositor_context_provider_ = nullptr;
+    video_frame_compositor_task_runner_->ReleaseSoon(FROM_HERE,
+                                                     context_provider_ptr);
+  }
 
   scoped_refptr<gpu::GpuChannelHost> gpu_channel_host =
       EstablishGpuChannelSync();

content/renderer/render_thread_impl.h

@@ -504,6 +504,14 @@ class CONTENT_EXPORT RenderThreadImpl
   scoped_refptr<base::SingleThreadTaskRunner>
   CreateVideoFrameCompositorTaskRunner();
 
+  // In the case of kOnDemand, we wont be using the task_runner created in
+  // CreateVideoFrameCompositorTaskRunner.
+  // TODO(https://crbug/901513): Remove once kOnDemand is removed.
+  void SetVideoFrameCompositorTaskRunner(
+      scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
+    video_frame_compositor_task_runner_ = task_runner;
+  }
+
  private:
   void OnProcessFinalRelease() override;
   // IPC::Listener