Converts MaximizeModeWindowManager to use ash/common types

ash/mus/bridge/wm_window_mus.cc

 // 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/mus/bridge/wm_window_mus.h"
 
 #include "ash/common/wm/container_finder.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm_layout_manager.h"
 #include "ash/common/wm_window_observer.h"
@@ skipping 697 matching lines @@
 }
 
 void WmWindowMus::AddObserver(WmWindowObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void WmWindowMus::RemoveObserver(WmWindowObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
+bool WmWindowMus::HasObserver(const WmWindowObserver* observer) const {
+  return observers_.HasObserver(observer);
+}
+
 void WmWindowMus::OnTreeChanging(const TreeChangeParams& params) {
   WmWindowObserver::TreeChangeParams wm_params;
   wm_params.target = Get(params.target);
   wm_params.new_parent = Get(params.new_parent);
   wm_params.old_parent = Get(params.old_parent);
   FOR_EACH_OBSERVER(WmWindowObserver, observers_,
                     OnWindowTreeChanging(this, wm_params));
 }
 
 void WmWindowMus::OnTreeChanged(const TreeChangeParams& params) {
@@ skipping 42 matching lines @@
 void WmWindowMus::OnWindowDestroying(::mus::Window* window) {
   FOR_EACH_OBSERVER(WmWindowObserver, observers_, OnWindowDestroying(this));
 }
 
 void WmWindowMus::OnWindowDestroyed(::mus::Window* window) {
   FOR_EACH_OBSERVER(WmWindowObserver, observers_, OnWindowDestroyed(this));
 }
 
 }  // namespace mus
 }  // namespace ash