cc: Fix size_t to int truncations in tiles/ and trees/

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 <map>
 #include <set>
 #include <string>
@@ skipping 789 matching lines @@
  protected:
   friend class TreeSynchronizer;
 
   // This flag is set when the layer needs to push properties to the active
   // side.
   bool needs_push_properties_;
 
   // The number of direct children or dependent layers that need to be recursed
   // to in order for them or a descendent of them to push properties to the
   // active side.
-  int num_dependents_need_push_properties_;
+  size_t num_dependents_need_push_properties_;
 
   // Layers that share a sorting context id will be sorted together in 3d
   // space.  0 is a special value that means this layer will not be sorted and
   // will be drawn in paint order.
   int sorting_context_id_;
 
   DrawMode current_draw_mode_;
 
  private:
   // Rect indicating what was repainted/updated during update.
@@ skipping 26 matching lines @@
   bool visited_;
   bool layer_or_descendant_is_drawn_;
   bool sorted_for_recursion_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_