Update from https://crrev.com/316786

cc/output/overlay_strategy_single_on_top.h

 // Copyright 2014 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_OUTPUT_OVERLAY_STRATEGY_SINGLE_ON_TOP_H_
 #define CC_OUTPUT_OVERLAY_STRATEGY_SINGLE_ON_TOP_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
@@ skipping 11 matching lines @@
   OverlayStrategySingleOnTop(OverlayCandidateValidator* capability_checker,
                              ResourceProvider* resource_provider);
   bool Attempt(RenderPassList* render_passes_in_draw_order,
                OverlayCandidateList* candidate_list) override;
 
  private:
   bool IsOverlayQuad(const DrawQuad* draw_quad);
   bool GetCandidateQuadInfo(const DrawQuad& draw_quad,
                             OverlayCandidate* quad_info);
 
+  // Returns true if |draw_quad| will not block quads underneath from becoming
+  // an overlay.
+  bool IsInvisibleQuad(const DrawQuad* draw_quad);
+
   bool GetTextureQuadInfo(const TextureDrawQuad& quad,
                           OverlayCandidate* quad_info);
   bool GetVideoQuadInfo(const StreamVideoDrawQuad& quad,
                         OverlayCandidate* quad_info);
 
   OverlayCandidateValidator* capability_checker_;
   ResourceProvider* resource_provider_;
   DISALLOW_COPY_AND_ASSIGN(OverlayStrategySingleOnTop);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OVERLAY_STRATEGY_SINGLE_ON_TOP_H_