Remove ash dependency.

ash/devtools/window_element.cc

Index: ash/devtools/window_element.cc
diff --git a/ash/devtools/window_element.cc b/ash/devtools/window_element.cc
index fa9ee2c76c51648a1b84aa49348f55de28565c59..1310c18a0ea049826867b0236f63a0a2f2f5fa4c 100644
--- a/ash/devtools/window_element.cc
+++ b/ash/devtools/window_element.cc
@@ -38,6 +38,7 @@ WindowElement::~WindowElement() {
 void WindowElement::OnWindowHierarchyChanging(
     const aura::WindowObserver::HierarchyChangeParams& params) {
   if (params.target == window_) {
+    LOG(ERROR) << __PRETTY_FUNCTION__;
     parent()->RemoveChild(this);
     delete this;
   }
@@ -47,8 +48,12 @@ void WindowElement::OnWindowHierarchyChanging(
 void WindowElement::OnWindowHierarchyChanged(
     const aura::WindowObserver::HierarchyChangeParams& params) {
   if (window_ == params.new_parent && params.receiver == params.new_parent) {
+    LOG(ERROR) << __PRETTY_FUNCTION__;
     if (delegate()->IsHighlightingWindow(params.target))
       return;
+    LOG(ERROR) << __PRETTY_FUNCTION__ << " node_id: " << node_id()
+               << " -- window_ bounds: "
+               << window_->GetBoundsInScreen().ToString();
     AddChild(new WindowElement(params.target, delegate(), this),
              children().empty() ? nullptr : children().back());
   }