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

cc/trees/property_tree.cc

Index: cc/trees/property_tree.cc
diff --git a/cc/trees/property_tree.cc b/cc/trees/property_tree.cc
index 64209e936ba1423418c2ce0ea9a5ea4ea9a6b876..29d5a051754b793a303769ef7f715e9a8603c9e7 100644
--- a/cc/trees/property_tree.cc
+++ b/cc/trees/property_tree.cc
@@ -137,6 +137,7 @@ TransformNodeData::TransformNodeData()
       node_and_ancestors_have_only_integer_translation(true),
       scrolls(false),
       needs_sublayer_scale(false),
+      is_3d_sorted(false),
       affected_by_inner_viewport_bounds_delta_x(false),
       affected_by_inner_viewport_bounds_delta_y(false),
       affected_by_outer_viewport_bounds_delta_x(false),
@@ -173,6 +174,7 @@ bool TransformNodeData::operator==(const TransformNodeData& other) const {
              other.node_and_ancestors_have_only_integer_translation &&
          scrolls == other.scrolls &&
          needs_sublayer_scale == other.needs_sublayer_scale &&
+         is_3d_sorted == other.is_3d_sorted &&
          affected_by_inner_viewport_bounds_delta_x ==
              other.affected_by_inner_viewport_bounds_delta_x &&
          affected_by_inner_viewport_bounds_delta_y ==
@@ -254,6 +256,7 @@ void TransformNodeData::ToProtobuf(proto::TreeNode* proto) const {
       node_and_ancestors_have_only_integer_translation);
   data->set_scrolls(scrolls);
   data->set_needs_sublayer_scale(needs_sublayer_scale);
+  data->set_is_3d_sorted(is_3d_sorted);
 
   data->set_affected_by_inner_viewport_bounds_delta_x(
       affected_by_inner_viewport_bounds_delta_x);
@@ -318,6 +321,7 @@ void TransformNodeData::FromProtobuf(const proto::TreeNode& proto) {
       data.node_and_ancestors_have_only_integer_translation();
   scrolls = data.scrolls();
   needs_sublayer_scale = data.needs_sublayer_scale();
+  is_3d_sorted = data.is_3d_sorted();
 
   affected_by_inner_viewport_bounds_delta_x =
       data.affected_by_inner_viewport_bounds_delta_x();