Decouple BrowserCompositorOutputSurface from BeginFrameSource.

content/browser/compositor/mus_browser_compositor_output_surface.h

Index: content/browser/compositor/mus_browser_compositor_output_surface.h
diff --git a/content/browser/compositor/mus_browser_compositor_output_surface.h b/content/browser/compositor/mus_browser_compositor_output_surface.h
index 476f4524b86dedb482f11f8b28df57f6dbe50a59..115999b4bc88e8a79a6cf9df47d29b4251ef1967 100644
--- a/content/browser/compositor/mus_browser_compositor_output_surface.h
+++ b/content/browser/compositor/mus_browser_compositor_output_surface.h
@@ -45,7 +45,6 @@ class MusBrowserCompositorOutputSurface
       scoped_refptr<ContextProviderCommandBuffer> context,
       gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
       scoped_refptr<ui::CompositorVSyncManager> vsync_manager,
-      cc::SyntheticBeginFrameSource* begin_frame_source,
       std::unique_ptr<display_compositor::CompositorOverlayCandidateValidator>
           overlay_candidate_validator);
 
@@ -54,7 +53,6 @@ class MusBrowserCompositorOutputSurface
       scoped_refptr<ContextProviderCommandBuffer> context,
       gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
       scoped_refptr<ui::CompositorVSyncManager> vsync_manager,
-      cc::SyntheticBeginFrameSource* begin_frame_source,
       std::unique_ptr<display_compositor::CompositorOverlayCandidateValidator>
           overlay_candidate_validator);