cc : Add LayerToPropertyTreeIndices map to PropertyTrees

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index 019f62048dd03b09c5ce7272c743e6b8ab2aa359..94d6f76850f9d749e763d9da8c0b11e0397b220c 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -101,6 +101,7 @@ LayerImpl::~LayerImpl() {
   layer_tree_impl_->UnregisterScrollLayer(this);
   layer_tree_impl_->UnregisterLayer(this);
   layer_tree_impl_->RemoveLayerShouldPushProperties(this);
+  layer_tree_impl_->RemoveFromLayerToPropertyTreeIndicesMap(layer_id_);
 
   layer_tree_impl_->RemoveFromElementMap(this);
 
@@ -181,21 +182,33 @@ void LayerImpl::ApplyScroll(ScrollState* scroll_state) {
 
 void LayerImpl::SetTransformTreeIndex(int index) {
   transform_tree_index_ = index;
+  if (layer_tree_impl_)

[ajuma, 2016/05/12 00:54:56]

Is layer_tree_impl_ ever null? It's assumed to be non-null in lots of places in
LayerImpl.

+    layer_tree_impl()->UpdateLayerToPropertyTreeIndicesMap(
+        id(), index, PropertyTrees::Types::TRANSFORM_TREE);
   SetNeedsPushProperties();
 }
 
 void LayerImpl::SetClipTreeIndex(int index) {
   clip_tree_index_ = index;
+  if (layer_tree_impl_)
+    layer_tree_impl()->UpdateLayerToPropertyTreeIndicesMap(
+        id(), index, PropertyTrees::Types::CLIP_TREE);
   SetNeedsPushProperties();
 }
 
 void LayerImpl::SetEffectTreeIndex(int index) {
   effect_tree_index_ = index;
+  if (layer_tree_impl_)
+    layer_tree_impl()->UpdateLayerToPropertyTreeIndicesMap(
+        id(), index, PropertyTrees::Types::EFFECT_TREE);
   SetNeedsPushProperties();
 }
 
 void LayerImpl::SetScrollTreeIndex(int index) {
   scroll_tree_index_ = index;
+  if (layer_tree_impl_)
+    layer_tree_impl()->UpdateLayerToPropertyTreeIndicesMap(
+        id(), index, PropertyTrees::Types::SCROLL_TREE);
   SetNeedsPushProperties();
 }