cc: Implement overdraw feedback debugging feature.

ui/compositor/compositor.cc

 // Copyright (c) 2012 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.
 
 #include "ui/compositor/compositor.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <deque>
@@ skipping 122 matching lines @@
   }
   settings.renderer_settings.partial_swap_enabled =
       !command_line->HasSwitch(switches::kUIDisablePartialSwap);
 #if defined(OS_WIN)
   settings.renderer_settings.finish_rendering_on_resize = true;
 #elif defined(OS_MACOSX)
   settings.renderer_settings.release_overlay_resources_after_gpu_query = true;
 #endif
   settings.renderer_settings.gl_composited_texture_quad_border =
       command_line->HasSwitch(cc::switches::kGlCompositedTextureQuadBorder);
+  settings.renderer_settings.show_overdraw_feedback =
+      command_line->HasSwitch(cc::switches::kShowOverdrawFeedback);
 
   // These flags should be mirrored by renderer versions in content/renderer/.
   settings.initial_debug_state.show_debug_borders =
       command_line->HasSwitch(cc::switches::kUIShowCompositedLayerBorders);
   settings.initial_debug_state.show_fps_counter =
       command_line->HasSwitch(cc::switches::kUIShowFPSCounter);
   settings.initial_debug_state.show_layer_animation_bounds_rects =
       command_line->HasSwitch(cc::switches::kUIShowLayerAnimationBounds);
   settings.initial_debug_state.show_paint_rects =
       command_line->HasSwitch(switches::kUIShowPaintRects);
@@ skipping 417 matching lines @@
   for (auto& observer : observer_list_)
     observer.OnCompositingLockStateChanged(this);
 }
 
 void Compositor::CancelCompositorLock() {
   if (compositor_lock_)
     compositor_lock_->CancelLock();
 }
 
 }  // namespace ui