Makes tile-creation lazy

cc/resources/tile.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_RESOURCES_TILE_H_
 #define CC_RESOURCES_TILE_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "cc/resources/managed_tile_state.h"
 #include "cc/resources/picture_pile_impl.h"
 #include "cc/resources/tile_priority.h"
 #include "cc/trees/layer_tree_host_impl.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 
 namespace cc {
 
 class Tile;
 class TileManager;
 
 class CC_EXPORT Tile : public base::RefCounted<Tile> {
  public:
   Tile(TileManager* tile_manager,
        PicturePileImpl* picture_pile,
        gfx::Size tile_size,
        GLenum format,
        gfx::Rect content_rect,
+       gfx::Rect paint_rect,
        gfx::Rect opaque_rect,
        float contents_scale,
        int layer_id);
 
   PicturePileImpl* picture_pile() {
     return picture_pile_.get();
   }
 
   const TilePriority& priority(WhichTree tree) const {
     return priority_[tree];
@@ skipping 12 matching lines @@
     return managed_state_.drawing_info;
   }
   ManagedTileState::DrawingInfo& drawing_info() {
     return managed_state_.drawing_info;
   }
 
   const gfx::Rect& opaque_rect() const { return opaque_rect_; }
 
   float contents_scale() const { return contents_scale_; }
   gfx::Rect content_rect() const { return content_rect_; }
+  gfx::Rect paint_rect() const { return paint_rect_; }
 
   int layer_id() const { return layer_id_; }
 
   void set_picture_pile(scoped_refptr<PicturePileImpl> pile) {
    DCHECK(pile->CanRaster(contents_scale_, content_rect_));
    picture_pile_ = pile;
   }
 
  private:
   // Methods called by by tile manager.
@@ skipping 10 matching lines @@
 
   // Normal private methods.
   friend class base::RefCounted<Tile>;
   ~Tile();
 
   TileManager* tile_manager_;
   scoped_refptr<PicturePileImpl> picture_pile_;
   gfx::Rect tile_size_;
   GLenum format_;
   gfx::Rect content_rect_;
+  gfx::Rect paint_rect_;

[enne (OOO), 2013/03/27 22:15:39]

As a follow-up to whunt's offline question about storing paint_rect instead of
content_rect here, I don't think that's possible.  Two tilings can share the
same tile using the same picture pile but have different paint rects (because
the layer size shrank, for example).  Between paint rect and content rect, the
content rect of the tile is the constant shared piece of information between
both tilings using that tile.

   float contents_scale_;
   gfx::Rect opaque_rect_;
 
   TilePriority priority_[NUM_BIN_PRIORITIES];
   ManagedTileState managed_state_;
   int layer_id_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_TILE_H_