cc: Heapify pointers instead of objects in eviction tile priority queue.

cc/resources/eviction_tile_priority_queue.h

Index: cc/resources/eviction_tile_priority_queue.h
diff --git a/cc/resources/eviction_tile_priority_queue.h b/cc/resources/eviction_tile_priority_queue.h
index 3b02c962c027ce3af5ec786275c9ba4059bc5502..e91f0d2a682dc7e140bf40baeeaf334dc61b9d90 100644
--- a/cc/resources/eviction_tile_priority_queue.h
+++ b/cc/resources/eviction_tile_priority_queue.h
@@ -47,7 +47,10 @@ class CC_EXPORT EvictionTilePriorityQueue {
   void Pop();
 
  private:
-  std::vector<PairedPictureLayerQueue> paired_queues_;
+  // TODO(vmpstr): This is potentially unnecessary if it becomes the case that
+  // PairedPictureLayerQueue is fast enough to copy. In that case, we can use
+  // objects directly (ie std::vector<PairedPictureLayerQueue>).
+  ScopedPtrVector<PairedPictureLayerQueue> paired_queues_;
   TreePriority tree_priority_;
 
   DISALLOW_COPY_AND_ASSIGN(EvictionTilePriorityQueue);