cc: Compute target space transform dynamically

cc/trees/transform_node.h

 // Copyright 2016 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_TRANSFORM_NODE_H_
 #define CC_TREES_TRANSFORM_NODE_H_
 
 #include "cc/base/cc_export.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/scroll_offset.h"
@@ skipping 52 matching lines @@
   // special value and indicates that the node is not in any 3d rendering
   // context.
   int sorting_context_id;
 
   // TODO(vollick): will be moved when accelerated effects are implemented.
   bool needs_local_transform_update : 1;
 
   bool node_and_ancestors_are_animated_or_invertible : 1;
 
   bool is_invertible : 1;
-  bool ancestors_are_invertible : 1;
+  mutable bool ancestors_are_invertible : 1;

[ajuma, 2016/07/22 18:29:40]

See earlier comment about this. Instead of allowing the new code path to mutate
this value, perhaps it can separately cache whether the draw transform is
invertible.

[sunxd, 2016/07/22 20:25:03]

Done.

 
   bool has_potential_animation : 1;
   bool is_currently_animating : 1;
   bool to_screen_is_potentially_animated : 1;
   bool has_only_translation_animations : 1;
 
   // Flattening, when needed, is only applied to a node's inherited transform,
   // never to its local transform.
   bool flattens_inherited_transform : 1;
 
@@ skipping 75 matching lines @@
 
   bool operator==(const TransformCachedNodeData& other) const;
 
   void ToProtobuf(proto::TransformCachedNodeData* proto) const;
   void FromProtobuf(const proto::TransformCachedNodeData& proto);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_TRANSFORM_NODE_H_