Move default begin frame sources out to mus

services/ui/public/cpp/gpu_service.h

Index: services/ui/public/cpp/gpu_service.h
diff --git a/services/ui/public/cpp/gpu_service.h b/services/ui/public/cpp/gpu_service.h
index 89290315d65979c664e75bbd5ef7653e9da235fb..19baa04c401798ee885d527b0e4f43cacfc013aa 100644
--- a/services/ui/public/cpp/gpu_service.h
+++ b/services/ui/public/cpp/gpu_service.h
@@ -44,6 +44,10 @@ class GpuService : public gpu::GpuChannelHostFactory,
   scoped_refptr<gpu::GpuChannelHost> EstablishGpuChannelSync() override;
   gpu::GpuMemoryBufferManager* GetGpuMemoryBufferManager() override;
 
+  scoped_refptr<base::SingleThreadTaskRunner> main_task_runner() {

[enne (OOO), 2016/08/19 20:52:22]

I have no idea what I'm doing here, but this looked like the most plausible task
runner.

+    return main_task_runner_;
+  }
+
  private:
   friend struct base::DefaultSingletonTraits<GpuService>;