Adds WmWindow and converts WindowState to use it

ash/wm/aura/wm_root_window_controller_aura.cc

Index: ash/wm/aura/wm_root_window_controller_aura.cc
diff --git a/ash/wm/aura/wm_root_window_controller_aura.cc b/ash/wm/aura/wm_root_window_controller_aura.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a8ed4cfee530883e3a1c463b8e5780128fec63af
--- /dev/null
+++ b/ash/wm/aura/wm_root_window_controller_aura.cc
@@ -0,0 +1,56 @@
+// Copyright 2016 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 "ash/wm/aura/wm_root_window_controller_aura.h"
+
+#include "ash/root_window_controller.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_property.h"
+
+DECLARE_WINDOW_PROPERTY_TYPE(ash::wm::WmRootWindowControllerAura*);
+
+namespace ash {
+namespace wm {
+
+// TODO(sky): it likely makes more sense to hang this off RootWindowSettings.
+DEFINE_OWNED_WINDOW_PROPERTY_KEY(ash::wm::WmRootWindowControllerAura,
+                                 kWmRootWindowControllerKey,
+                                 nullptr);
+
+WmRootWindowControllerAura::WmRootWindowControllerAura(
+    RootWindowController* root_window_controller)
+    : root_window_controller_(root_window_controller) {
+  root_window_controller_->GetRootWindow()->SetProperty(
+      kWmRootWindowControllerKey, this);
+}
+
+WmRootWindowControllerAura::~WmRootWindowControllerAura() {}
+
+// static
+const WmRootWindowControllerAura* WmRootWindowControllerAura::Get(
+    const aura::Window* window) {
+  if (!window)
+    return nullptr;
+
+  RootWindowController* root_window_controller =
+      GetRootWindowController(window);
+  if (!root_window_controller)
+    return nullptr;
+
+  WmRootWindowControllerAura* wm_root_window_controller =
+      root_window_controller->GetRootWindow()->GetProperty(
+          kWmRootWindowControllerKey);
+  if (wm_root_window_controller)
+    return wm_root_window_controller;
+
+  // WmRootWindowControllerAura is owned by the RootWindowController's window.
+  return new WmRootWindowControllerAura(root_window_controller);
+}
+
+bool WmRootWindowControllerAura::HasShelf() {
+  return root_window_controller_->shelf() != nullptr;
+}
+
+}  // namespace wm
+}  // namespace ash