Add a new command buffer function glScheduleCALayerInUseQueryCHROMIUM.

ui/gl/gl_surface.h

Index: ui/gl/gl_surface.h
diff --git a/ui/gl/gl_surface.h b/ui/gl/gl_surface.h
index c7fbf46e2cd6a2c5de4c595550cc87922df6e9a2..9fca48f98d9f9c913d468fab69c3c03715ff7df4 100644
--- a/ui/gl/gl_surface.h
+++ b/ui/gl/gl_surface.h
@@ -184,6 +184,12 @@ class GL_EXPORT GLSurface : public base::RefCounted<GLSurface> {
                                const gfx::Transform& transform,
                                int sorting_content_id,
                                unsigned filter);
+  struct CALayerInUseQuery {
+    unsigned texture;
+    GLImage* image;

[piman, 2016/06/14 00:58:56]

I think you want to take a scoped_refptr<GLImage> here, in case the client
destroys the image before the swap.

Side note, we should probably document the semantics in that case.

[erikchen, 2016/06/14 01:47:51]

ImageTransportSurfaceOverlayMac holds on to the underlying IOSurfaceRef, not the
GLImage. That being said, I prefer smart pointers to raw pointers, so I made the
change anyways.

I documented the semantics more clearly in CHROMIUM_schedule_ca_layer.txt.

"""
Clients should not destroy any textures while they are being queried, as the
swap ACK will use the original texture id to identify the queried textures.
"""
Note that there is never any confusion from the service, since |texture| is
treated as an opaque id.

I also updated the documentation in ImageTransportSurfaceOverlayMac
"""
	 109     // It's possible that the client will have destroyed the texture
before
 110     // SwapBuffersInternal is called. It's important that |texture| is only
used
 111     // as an opaque identifier, since it may no longer point to the same
 112     // texture."""

+  };
+  virtual void ScheduleCALayerInUseQuery(
+      std::vector<CALayerInUseQuery> queries);
 
   virtual bool IsSurfaceless() const;