cc : Move LayerImpl::parent to test properties

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 900ee29e5747f32de7d18699977f3abfee5440c2..8ba97c3daa2819e406422eae91a02284f0db8c7c 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -44,8 +44,7 @@
 
 namespace cc {
 LayerImpl::LayerImpl(LayerTreeImpl* tree_impl, int id)
-    : parent_(nullptr),
-      layer_id_(id),
+    : layer_id_(id),
       layer_tree_impl_(tree_impl),
       test_properties_(nullptr),
       scroll_clip_layer_id_(Layer::INVALID_ID),
@@ -102,7 +101,7 @@ LayerImpl::~LayerImpl() {
 }
 
 void LayerImpl::AddChild(std::unique_ptr<LayerImpl> child) {
-  child->SetParent(this);
+  child->test_properties()->parent = this;
   DCHECK_EQ(layer_tree_impl(), child->layer_tree_impl());
   test_properties()->children.push_back(child.get());
   layer_tree_impl_->AddLayer(std::move(child));
@@ -117,10 +116,6 @@ std::unique_ptr<LayerImpl> LayerImpl::RemoveChildForTesting(LayerImpl* child) {
   return layer_tree_impl_->RemoveLayer(child->id());
 }
 
-void LayerImpl::SetParent(LayerImpl* parent) {
-  parent_ = parent;
-}
-
 void LayerImpl::SetHasWillChangeTransformHint(bool has_will_change) {
   if (has_will_change_transform_hint_ == has_will_change)
     return;