cc: Plumbing for BeginFrameSource based on Surfaces

cc/surfaces/onscreen_display_client.h

Index: cc/surfaces/onscreen_display_client.h
diff --git a/cc/surfaces/onscreen_display_client.h b/cc/surfaces/onscreen_display_client.h
index 4c4245d4161eb3e04120f582ce04fed82c8a3872..30943066d3dc4d8518682f6a9ae3b245eecc0617 100644
--- a/cc/surfaces/onscreen_display_client.h
+++ b/cc/surfaces/onscreen_display_client.h
@@ -53,11 +53,14 @@ class CC_SURFACES_EXPORT OnscreenDisplayClient
 
  protected:
   scoped_ptr<OutputSurface> output_surface_;
-  scoped_ptr<Display> display_;
+  // Be careful of destruction order:
+  // Display depends on DisplayScheduler depends on *BeginFrameSource
+  // depends on TaskRunner.

[mithro-old, 2015/10/01 03:00:23]

Can we use asserts/dchecks to make sure the destruction happens in the right
order?

[brianderson, 2015/10/07 20:54:48]

Trying to think of how to do that, but it's difficult since the classes here are
given non-owning pointers and are not notified that something they depend on is
going to be destroyed.
 
The trybots caught it, so I'm not too worried about this regressing.

+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_ptr<SyntheticBeginFrameSource> synthetic_frame_source_;
   scoped_ptr<BackToBackBeginFrameSource> unthrottled_frame_source_;
   scoped_ptr<DisplayScheduler> scheduler_;
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  scoped_ptr<Display> display_;
   SurfaceDisplayOutputSurface* surface_display_output_surface_;
   bool output_surface_lost_;
   bool disable_display_vsync_;