Update from https://crrev.com/320343

cc/trees/property_tree.h

 // Copyright 2014 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_TREES_PROPERTY_TREE_H_
 #define CC_TREES_PROPERTY_TREE_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 51 matching lines @@
 
   // TODO(vollick): will be moved when accelerated effects are implemented.
   bool needs_local_transform_update;
 
   bool is_invertible;
   bool ancestors_are_invertible;
 
   bool is_animated;
   bool to_screen_is_animated;
 
-  bool flattens;
+  // We don't necessarily create a transform node to apply flattening. If we've
+  // skipped flattening for an ancestor, we must flatten the transform we
+  // inherit, but we don't necessarily need to flatten our local transform. We
+  // must therefore use two values to describe the flattening required for the
+  // local and inherited transforms.
+  bool flattens_inherited_transform;
+  bool flattens_local_transform;
   bool scrolls;
 
   bool needs_sublayer_scale;
   // This is used as a fallback when we either cannot adjust raster scale or if
   // the raster scale cannot be extracted from the screen space transform.
   float layer_scale_factor;
   gfx::Vector2dF sublayer_scale;
 
   // TODO(vollick): will be moved when accelerated effects are implemented.
   gfx::Vector2dF scroll_offset;
@@ skipping 99 matching lines @@
   void UpdateSnapping(TransformNode* node);
 };
 
 class CC_EXPORT ClipTree final : public PropertyTree<ClipNode> {};
 
 class CC_EXPORT OpacityTree final : public PropertyTree<OpacityNode> {};
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_