Clean up WTH creation

mojo/aura/window_tree_host_mojo.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/aura/window_tree_host_mojo.h"
 
 #include <vector>
 
 #include "mojo/aura/window_tree_host_mojo_delegate.h"
 #include "ui/aura/env.h"
@@ skipping 43 matching lines @@
   Managers managers_;
 
   DISALLOW_COPY_AND_ASSIGN(TreeHosts);
 };
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeHostMojo, public:
 
-WindowTreeHostMojo::WindowTreeHostMojo(const gfx::Rect& bounds,
+WindowTreeHostMojo::WindowTreeHostMojo(view_manager::Node* node,
                                        WindowTreeHostMojoDelegate* delegate)
-    : bounds_(bounds),
+    : node_(node),
+      bounds_(node->bounds()),
       delegate_(delegate) {
+  node_->AddObserver(this);
   CreateCompositor(GetAcceleratedWidget());
 
   TreeHosts::Get()->Add(this);
 }
 
 WindowTreeHostMojo::~WindowTreeHostMojo() {
+  node_->RemoveObserver(this);
   TreeHosts::Get()->Remove(this);
   DestroyCompositor();
   DestroyDispatcher();
 }
 
 // static
 WindowTreeHostMojo* WindowTreeHostMojo::ForCompositor(
     ui::Compositor* compositor) {
   const Managers& managers = TreeHosts::Get()->managers();
   for (size_t i = 0; i < managers.size(); ++i) {
@@ skipping 67 matching lines @@
   NOTIMPLEMENTED();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeHostMojo, ui::EventSource implementation:
 
 ui::EventProcessor* WindowTreeHostMojo::GetEventProcessor() {
   return dispatcher();
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// WindowTreeHostMojo, view_manager::NodeObserver implementation:
+
+void WindowTreeHostMojo::OnNodeBoundsChange(
+    view_manager::Node* node,
+    const gfx::Rect& old_bounds,
+    const gfx::Rect& new_bounds,
+    view_manager::NodeObserver::DispositionChangePhase phase) {
+  bounds_ = new_bounds;
+  if (old_bounds.origin() != new_bounds.origin())
+    OnHostMoved(bounds_.origin());
+  if (old_bounds.size() != new_bounds.size())
+    OnHostResized(bounds_.size());
+}
+
 }  // namespace mojo