cc: Added tile bundles

cc/resources/picture_layer_tiling_set.cc

Index: cc/resources/picture_layer_tiling_set.cc
diff --git a/cc/resources/picture_layer_tiling_set.cc b/cc/resources/picture_layer_tiling_set.cc
index 5ad26506fd768c7b83f7c5324dfd8abf4e13adef..654b1808306d2259a0dee09f8d0ab174f0023aea 100644
--- a/cc/resources/picture_layer_tiling_set.cc
+++ b/cc/resources/picture_layer_tiling_set.cc
@@ -212,6 +212,12 @@ Tile* PictureLayerTilingSet::CoverageIterator::operator*() const {
   return *tiling_iter_;
 }
 
+TilePriority PictureLayerTilingSet::CoverageIterator::priority() {
+  if (!tiling_iter_)
+    return TilePriority();
+  return tiling_iter_.priority();
+}
+
 PictureLayerTiling* PictureLayerTilingSet::CoverageIterator::CurrentTiling() {
   if (current_tiling_ < 0)
     return NULL;