cc: Move render surface ownership from layers to the effect tree

cc/trees/damage_tracker.cc

 // Copyright 2011 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 "cc/trees/damage_tracker.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 174 matching lines @@
   for (size_t layer_index = 0; layer_index < layer_list.size(); ++layer_index) {
     // Visit layers in back-to-front order.
     LayerImpl* layer = layer_list[layer_index];
 
     // We skip damage from the HUD layer because (a) the HUD layer damages the
     // whole frame and (b) we don't want HUD layer damage to be shown by the
     // HUD damage rect visualization.
     if (layer == layer->layer_tree_impl()->hud_layer())
       continue;
 
-    if (layer->render_surface() && layer->render_surface() != target_surface)
-      ExtendDamageForRenderSurface(layer->render_surface(), &damage);
+    RenderSurfaceImpl* render_surface = layer->render_surface();
+    if (render_surface && render_surface != target_surface)
+      ExtendDamageForRenderSurface(render_surface, &damage);
     else
       ExtendDamageForLayer(layer, &damage);
   }
 
   return damage;
 }
 
 DamageTracker::DamageAccumulator DamageTracker::TrackDamageFromSurfaceMask(
     LayerImpl* target_surface_mask_layer) {
   DamageAccumulator damage;
@@ skipping 231 matching lines @@
   }
 
   rect->set_x(x_);
   rect->set_y(y_);
   rect->set_width(width.ValueOrDie());
   rect->set_height(height.ValueOrDie());
   return true;
 }
 
 }  // namespace cc