cc: Start using raster/eviction iterators in tile manager

cc/resources/picture_layer_tiling.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_PICTURE_LAYER_TILING_H_
 #define CC_RESOURCES_PICTURE_LAYER_TILING_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 41 matching lines @@
     ~TilingRasterTileIterator();
 
     operator bool() const {
       return current_tile_ && TileNeedsRaster(current_tile_);
     }
     Tile* operator*() { return current_tile_; }
     TilePriority::PriorityBin get_type() const { return type_; }
 
     TilingRasterTileIterator& operator++();
 
+    bool HasTilesRequiredForActivation() const;

[reveman, 2014/04/24 00:17:34]

hm, this returns some state that depend on the position of the iterator and all
following elements. I think it's a bad idea to have such a function on an
iterator. If we can't land some change prior to this that moves the decision
whether we can activate to tile initialization completion time, could we instead
add a TilesRequiredForActivationAndNeedRasterCount() function to the
PictureLayerTiling class and use that in the tile manager instead?

[vmpstr, 2014/04/28 18:50:37]

Moved this to a separate patch.

+
     gfx::Rect TileBounds() const {
       DCHECK(*this);
       if (type_ == TilePriority::NOW) {
         return tiling_->tiling_data_.TileBounds(visible_iterator_.index_x(),
                                                 visible_iterator_.index_y());
       }
       return tiling_->tiling_data_.TileBounds(spiral_iterator_.index_x(),
                                               spiral_iterator_.index_y());
     }
 
@@ skipping 234 matching lines @@
 
  private:
   DISALLOW_ASSIGN(PictureLayerTiling);
 
   RectExpansionCache expansion_cache_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_H_