Decouple BrowserCompositorOutputSurface from BeginFrameSource.

content/browser/compositor/mus_browser_compositor_output_surface.cc

Index: content/browser/compositor/mus_browser_compositor_output_surface.cc
diff --git a/content/browser/compositor/mus_browser_compositor_output_surface.cc b/content/browser/compositor/mus_browser_compositor_output_surface.cc
index acea5da8602c8255627a6bfc10ac40aa0ce09c50..686b88adddf5e64b863e74b5e4bc86e659aecb56 100644
--- a/content/browser/compositor/mus_browser_compositor_output_surface.cc
+++ b/content/browser/compositor/mus_browser_compositor_output_surface.cc
@@ -27,12 +27,10 @@ MusBrowserCompositorOutputSurface::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)
     : GpuBrowserCompositorOutputSurface(std::move(context),
                                         std::move(vsync_manager),
-                                        begin_frame_source,
                                         std::move(overlay_candidate_validator)),
       ui_window_(window) {
   ui_compositor_frame_sink_ = ui_window_->RequestCompositorFrameSink(
@@ -46,12 +44,10 @@ MusBrowserCompositorOutputSurface::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)
     : GpuBrowserCompositorOutputSurface(std::move(context),
                                         std::move(vsync_manager),
-                                        begin_frame_source,
                                         std::move(overlay_candidate_validator)),
       window_(window) {
   aura::WindowPortMus* window_port = aura::WindowPortMus::Get(window_);