Mac Overlays: Add sandwich strategy

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 <vector>
 
 #include "cc/base/cc_export.h"
@@ skipping 23 matching lines @@
   gfx::OverlayTransform transform;
   // Format of the buffer to composite.
   ResourceFormat format;
   // Size of the resource, in pixels.
   gfx::Size resource_size_in_pixels;
   // Rect on the display to position the overlay to. Implementer must convert
   // 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;
+  // 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;
   // Stacking order of the overlay plane relative to the main surface,
   // which is 0. Signed to allow for "underlays".
   int plane_z_order;
 
   // To be modified by the implementer if this candidate can go into
   // an overlay.
   bool overlay_handled;
 };
 
 typedef std::vector<OverlayCandidate> OverlayCandidateList;
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OVERLAY_CANDIDATE_H_