Example MojoVideoDecoder decoder using the command buffer.

content/renderer/media/renderer_gpu_video_accelerator_factories.cc

Index: content/renderer/media/renderer_gpu_video_accelerator_factories.cc
diff --git a/content/renderer/media/renderer_gpu_video_accelerator_factories.cc b/content/renderer/media/renderer_gpu_video_accelerator_factories.cc
index c37c3f12bd06cb0afbc9b60a52d3a5a9df2d370c..aaff4a3c8e9e0617cc0768031e97393a47135267 100644
--- a/content/renderer/media/renderer_gpu_video_accelerator_factories.cc
+++ b/content/renderer/media/renderer_gpu_video_accelerator_factories.cc
@@ -128,6 +128,14 @@ base::UnguessableToken RendererGpuVideoAcceleratorFactories::GetChannelToken() {
   return channel_token_;
 }
 
+int32_t RendererGpuVideoAcceleratorFactories::GetCommandBufferRouteId() {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  if (!context_provider_)
+    return 0;
+  LOG(ERROR) << "stream_id should be: " << context_provider_->GetCommandBufferProxy()->GetExtraCommandBufferData();
+  return context_provider_->GetCommandBufferProxy()->route_id();
+}
+
 std::unique_ptr<media::VideoDecodeAccelerator>
 RendererGpuVideoAcceleratorFactories::CreateVideoDecodeAccelerator() {
   DCHECK(video_accelerator_enabled_);