Add SurfaceWillDraw notification

cc/test/fake_surface_observer.h

Index: cc/test/fake_surface_observer.h
diff --git a/cc/test/fake_surface_observer.h b/cc/test/fake_surface_observer.h
index ab0bab5d09202280189b19c3c82c11dc11d9bdcf..0ce2c23d4e2334b3b6df9223af66329b0699c582 100644
--- a/cc/test/fake_surface_observer.h
+++ b/cc/test/fake_surface_observer.h
@@ -24,6 +24,8 @@ class FakeSurfaceObserver : public SurfaceObserver {
 
   bool IsSurfaceDamaged(const SurfaceId& surface_id) const;
 
+  bool SurfaceWillDrawCalled(const SurfaceId& surface_id) const;
+
   const SurfaceId& last_created_surface_id() const {
     return last_created_surface_id_;
   }
@@ -41,10 +43,12 @@ class FakeSurfaceObserver : public SurfaceObserver {
   void OnSurfaceDestroyed(const SurfaceId& surface_id) override {}
   void OnSurfaceDamageExpected(const SurfaceId& surface_id,
                                const BeginFrameArgs& args) override {}
+  void OnSurfaceWillDraw(const SurfaceId& surface_id) override;
 
   bool damage_display_;
   BeginFrameAck last_ack_;
   base::flat_set<SurfaceId> damaged_surfaces_;
+  base::flat_set<SurfaceId> will_draw_surfaces_;
   SurfaceId last_created_surface_id_;
   SurfaceInfo last_surface_info_;
 };