cc: Add support for partial swaps when using impl-side painting.

cc/layers/layer_impl.cc

 // Copyright 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 "cc/layers/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/json/json_reader.h"
 #include "base/strings/stringprintf.h"
 #include "cc/animation/animation_registrar.h"
@@ skipping 999 matching lines @@
   Animation* transform_animation =
       layer_animation_controller_->GetAnimation(Animation::Transform);
   return transform_animation && transform_animation->is_impl_only();
 }
 
 void LayerImpl::SetUpdateRect(const gfx::RectF& update_rect) {
   update_rect_ = update_rect;
   SetNeedsPushProperties();
 }
 
+void LayerImpl::UnionDamageRect(gfx::Rect damage_rect) {
+  damage_rect_ = gfx::UnionRects(damage_rect_, damage_rect);
+}
+
 void LayerImpl::SetContentBounds(const gfx::Size& content_bounds) {
   if (this->content_bounds() == content_bounds)
     return;
 
   draw_properties_.content_bounds = content_bounds;
   NoteLayerPropertyChanged();
 }
 
 void LayerImpl::SetContentsScale(float contents_scale_x,
                                  float contents_scale_y) {
@@ skipping 470 matching lines @@
 scoped_ptr<base::Value> LayerImpl::AsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   AsValueInto(state.get());
   return state.PassAs<base::Value>();
 }
 
 void LayerImpl::RunMicroBenchmark(MicroBenchmarkImpl* benchmark) {
   benchmark->RunOnLayer(this);
 }
 }  // namespace cc