Merge 276305 "cc: Don't cleanup the pending twin's low res tiling."

cc/resources/picture_layer_tiling_set.cc

Index: cc/resources/picture_layer_tiling_set.cc
===================================================================
--- cc/resources/picture_layer_tiling_set.cc	(revision 276694)
+++ cc/resources/picture_layer_tiling_set.cc	(working copy)
@@ -109,12 +109,8 @@
 }
 
 PictureLayerTiling* PictureLayerTilingSet::AddTiling(float contents_scale) {
-  for (size_t i = 0; i < tilings_.size(); ++i) {
-    // TODO(enne): temporary sanity CHECK for http://crbug.com/358350.
-    // If a duplicate tiling gets added, then many assumptions in
-    // PictureLayerImpl fail.
-    CHECK_NE(tilings_[i]->contents_scale(), contents_scale);
-  }
+  for (size_t i = 0; i < tilings_.size(); ++i)
+    DCHECK_NE(tilings_[i]->contents_scale(), contents_scale);
 
   tilings_.push_back(PictureLayerTiling::Create(contents_scale,
                                                 layer_bounds_,