cc: Implement overdraw feedback debugging feature.

cc/output/gl_renderer.h

 // Copyright 2010 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_GL_RENDERER_H_
 #define CC_OUTPUT_GL_RENDERER_H_
 
 #include <deque>
 #include <vector>
 
@@ skipping 252 matching lines @@
       const CALayerOverlay* ca_layer_overlay,
       Resource** resource,
       DrawingFrame* frame,
       gfx::RectF* new_bounds);
 
   // Schedules the |ca_layer_overlay|, which is guaranteed to have a non-null
   // |rpdq| parameter.
   void ScheduleRenderPassDrawQuad(const CALayerOverlay* ca_layer_overlay,
                                   DrawingFrame* external_frame);
 
+  // Setup/flush all pending overdraw feedback to framebuffer.
+  void SetupOverdrawFeedback();
+  void FlushOverdrawFeedback(const DrawingFrame* frame,
+                             const gfx::Rect& output_rect);
+  // Process overdraw feedback from query.
+  using OverdrawFeedbackCallback = base::Callback<void(unsigned, int)>;
+  void ProcessOverdrawFeedback(std::vector<int>* overdraw,
+                               size_t num_expected_results,
+                               unsigned query,
+                               int multiplier);
+
   using OverlayResourceLock =
       std::unique_ptr<ResourceProvider::ScopedReadLockGL>;
   using OverlayResourceLockList = std::vector<OverlayResourceLock>;
 
   // Resources that have been sent to the GPU process, but not yet swapped.
   OverlayResourceLockList pending_overlay_resources_;
 
   // Resources that should be shortly swapped by the GPU process.
   std::deque<OverlayResourceLockList> swapping_overlay_resources_;
 
@@ skipping 63 matching lines @@
   // The method FlippedFramebuffer determines whether the framebuffer associated
   // with a DrawingFrame is flipped. It makes the assumption that the
   // DrawingFrame is being used as part of a render pass. If a DrawingFrame is
   // not being used as part of a render pass, setting it here forces
   // FlippedFramebuffer to return |true|.
   bool force_drawing_frame_framebuffer_unflipped_ = false;
 
   BoundGeometry bound_geometry_;
   ColorLUTCache color_lut_cache_;
 
+  unsigned offscreen_stencil_renderbuffer_id_ = 0;
+  gfx::Size offscreen_stencil_renderbuffer_size_;
+
   base::WeakPtrFactory<GLRenderer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GLRenderer);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_GL_RENDERER_H_