Add SurfaceWillDraw notification

cc/test/fake_surface_observer.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TEST_FAKE_SURFACE_OBSERVER_H_
 #define CC_TEST_FAKE_SURFACE_OBSERVER_H_
 
 #include "base/containers/flat_set.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/surfaces/surface_id.h"
 #include "cc/surfaces/surface_info.h"
 #include "cc/surfaces/surface_observer.h"
 
 namespace cc {
 
 class FakeSurfaceObserver : public SurfaceObserver {
  public:
   // If |damage_display| is true, the observer will indicate display damage when
   // a surface is damaged.
   explicit FakeSurfaceObserver(bool damage_display = true);
   virtual ~FakeSurfaceObserver();
 
   const BeginFrameAck& last_ack() const { return last_ack_; }
 
   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_;
   }
 
   const SurfaceInfo& last_surface_info() const { return last_surface_info_; }
 
   void Reset();
 
  private:
   // SurfaceObserver implementation:
   bool OnSurfaceDamaged(const SurfaceId& surface_id,
                         const BeginFrameAck& ack) override;
   void OnSurfaceCreated(const SurfaceInfo& surface_info) override;
   void OnSurfaceDiscarded(const SurfaceId& surface_id) override {}
   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_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_SURFACE_OBSERVER_H_