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

cc/layers/layer_impl.h

 // 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.
 
 #ifndef CC_LAYERS_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <set>
 #include <string>
 
@@ skipping 440 matching lines @@
   bool TransformIsAnimatingOnImplOnly() const;
   void SetTransformAndInvertibility(const gfx::Transform& transform,
                                     bool transform_is_invertible);
   bool transform_is_invertible() const { return transform_is_invertible_; }
 
   // Note this rect is in layer space (not content space).
   void SetUpdateRect(const gfx::RectF& update_rect);
 
   const gfx::RectF& update_rect() const { return update_rect_; }
 
+  void AddDamageRect(const gfx::RectF& damage_rect);
+
+  const gfx::RectF& damage_rect() const { return damage_rect_; }
+
   virtual base::DictionaryValue* LayerTreeAsJson() const;
 
   void SetStackingOrderChanged(bool stacking_order_changed);
 
   bool LayerPropertyChanged() const { return layer_property_changed_; }
 
   void ResetAllChangeTrackingForSubtree();
 
   LayerAnimationController* layer_animation_controller() {
     return layer_animation_controller_.get();
@@ skipping 181 matching lines @@
   int num_dependents_need_push_properties_;
 
   DrawMode current_draw_mode_;
 
  private:
   // Rect indicating what was repainted/updated during update.
   // Note that plugin layers bypass this and leave it empty.
   // Uses layer (not content) space.
   gfx::RectF update_rect_;
 
+  // This rect is in layer space.
+  gfx::RectF damage_rect_;
+
   // Manages animations for this layer.
   scoped_refptr<LayerAnimationController> layer_animation_controller_;
 
   // Manages scrollbars for this layer
   scoped_ptr<ScrollbarAnimationController> scrollbar_animation_controller_;
 
   scoped_ptr<ScrollbarSet> scrollbars_;
 
   ScopedPtrVector<CopyOutputRequest> copy_requests_;
 
   // Group of properties that need to be computed based on the layer tree
   // hierarchy before layers can be drawn.
   DrawProperties<LayerImpl> draw_properties_;
 
   scoped_refptr<base::debug::ConvertableToTraceFormat> debug_info_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_