cc:: Add transform nodes at boundaries of 3d rendering contexts

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 <stddef.h>
 
 #include <vector>
@@ skipping 100 matching lines @@
   // root is flat.
   bool node_and_ancestors_are_flat : 1;
 
   // This is needed to know if a layer can use lcd text.
   bool node_and_ancestors_have_only_integer_translation : 1;
 
   bool scrolls : 1;
 
   bool needs_sublayer_scale : 1;
 
+  bool is_3d_sorted : 1;

[weiliangc, 2016/01/25 21:29:26]

Can we have 3d rendering context within 3d rendering context? Is bool sufficient
or do we need an id?

[ajuma, 2016/01/25 21:53:00]

Looking at PaintLayer::renderingContextRoot (the id is just a hash of this
value), it seems possible to have:
A->B->C where A and C preserve-3d but B doesn't, resulting in all layers being
3d sorted but A and B having a different id than C. So I think we need an id
here.

+
   // These are used to position nodes wrt the right or bottom of the inner or
   // outer viewport.
   bool affected_by_inner_viewport_bounds_delta_x : 1;
   bool affected_by_inner_viewport_bounds_delta_y : 1;
   bool affected_by_outer_viewport_bounds_delta_x : 1;
   bool affected_by_outer_viewport_bounds_delta_y : 1;
 
   // Layer scale factor 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. For layers in the subtree of the page scale layer, the
@@ skipping 398 matching lines @@
   ClipTree clip_tree;
   ScrollTree scroll_tree;
   bool needs_rebuild;
   bool non_root_surfaces_enabled;
   int sequence_number;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_