cc: Don't subtract transparent overlay from damage.

cc/output/overlay_candidate.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_CANDIDATE_H_
 #define CC_OUTPUT_OVERLAY_CANDIDATE_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 49 matching lines @@
   // to integer coordinates if setting |overlay_handled| to true.
   gfx::RectF display_rect;
   // Crop within the buffer to be placed inside |display_rect|.
   gfx::RectF uv_rect;
   // Quad geometry rect after applying the quad_transform().
   gfx::Rect quad_rect_in_target_space;
   // Clip rect in the target content space after composition.
   gfx::Rect clip_rect;
   // If the quad is clipped after composition.
   bool is_clipped;
+  // If the quad doesn't require blending.
+  bool is_opaque;
   // True if the texture for this overlay should be the same one used by the
   // output surface's main overlay.
   bool use_output_surface_for_resource;
   // Texture resource to present in an overlay.
   unsigned resource_id;
 
 #if defined(OS_ANDROID)
   // For candidates from StreamVideoDrawQuads, this records whether the quad is
   // marked as being backed by a SurfaceTexture or not.  If so, it's not really
   // promotable to an overlay.
@@ skipping 42 matching lines @@
   // overlay, if one backs them with a SurfaceView.
   PromotionHintInfoMap promotion_hint_info_map_;
 
   // Helper to insert |candidate| into |promotion_hint_info_|.
   void AddPromotionHint(const OverlayCandidate& candidate);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OVERLAY_CANDIDATE_H_