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 435 matching lines @@
   void SetTransform(const gfx::Transform& transform);
   const gfx::Transform& transform() const { return transform_; }
   bool TransformIsAnimating() const;
   bool TransformIsAnimatingOnImplOnly() const;
 
   // 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 UnionDamageRect(gfx::Rect damage_rect);

[enne (OOO), 2014/04/14 17:08:29]

Can you name this function to be in the right space, e.g. UnionDamageLayerRect
or UnionDamageContentRect?

You are incorrectly unioning content space rects with layer rects.

[reveman, 2014/04/14 20:03:07]

Also, maybe more consistent to have this be SetDamageContentRect and leave it up
to the caller to do a union with damage_content_rect() if necessary?

[sohanjg, 2014/04/15 10:03:48]

Done.

[sohanjg, 2014/04/15 10:03:48]

In that case, the caller(LTHI) needs to maintain the unified damage rect for
each layer id, again involving a map.

+
+  void ResetDamageRect() { damage_rect_ = gfx::Rect(); }
+
+  const gfx::Rect& 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 178 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_;
 
+  gfx::Rect 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_