Removing the assumption that child->SetParent will not change Drawability

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index 737a26103dbbf4b3a9eda03a8682d823da76c29a..57c055b7fea3576c25ab680009ad6efe46a4f9c6 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -247,13 +247,13 @@ void Layer::AddChild(scoped_refptr<Layer> child) {
 void Layer::InsertChild(scoped_refptr<Layer> child, size_t index) {
   DCHECK(IsPropertyChangeAllowed());
   child->RemoveFromParent();
+  AddDrawableDescendants(child->NumDescendantsThatDrawContent() +
+                         (child->DrawsContent() ? 1 : 0));
   child->SetParent(this);
   child->stacking_order_changed_ = true;
 
   index = std::min(index, children_.size());
   children_.insert(children_.begin() + index, child);
-  AddDrawableDescendants(child->NumDescendantsThatDrawContent() +
-                         (child->DrawsContent() ? 1 : 0));
   SetNeedsFullTreeSync();
 }