implement the logic to set tile priorities based on current matrix

cc/picture_layer_impl.h

 // 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.
 
 #ifndef CC_PICTURE_LAYER_IMPL_H_
 #define CC_PICTURE_LAYER_IMPL_H_
 
 #include "cc/layer_impl.h"
 #include "cc/picture_layer_tiling.h"
 #include "cc/picture_layer_tiling_set.h"
@@ skipping 20 matching lines @@
   virtual void dumpLayerProperties(std::string*, int indent) const OVERRIDE;
   virtual void didUpdateTransforms() OVERRIDE;
 
   // PictureLayerTilingClient overrides.
   virtual scoped_refptr<Tile> CreateTile(PictureLayerTiling*,
                                          gfx::Rect) OVERRIDE;
 
   // PushPropertiesTo active tree => pending tree
   void SyncFromActiveLayer(const PictureLayerImpl* other);
 
+  void setBounds(const gfx::Size&);

[enne (OOO), 2012/12/04 01:13:27]

These three functions shadow the LayerImpl implementation.  I do not see how
they can get called.

I suspect you need to set these directly from PictureLayer::pushPropertiesTo
prior to calling Layer::pushPropertiesTo.

[qinmin, 2012/12/04 01:39:53]

These functions are to check whether bounds/scale changes. Layer don't have
scale info. Anyway, changed the code to record last scale and last bounds.
On 2012/12/04 01:13:27, enne wrote:

+  void setContentBounds(const gfx::Size&);
+  void setContentsScale(float contentsScaleX, float contentsScaleY);
 protected:
   PictureLayerImpl(int id);
 
   PictureLayerTilingSet tilings_;
   PicturePile pile_;
 
+  gfx::Transform last_screen_space_transform_;
+  double last_update_time_;
+
   friend class PictureLayer;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }
 
 #endif  // CC_PICTURE_LAYER_IMPL_H_