Converts MaximizeModeWindowManager to use ash/common types

ash/mus/bridge/wm_window_mus.h

 // 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.
 
 #ifndef ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_
 #define ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_
 
 #include <memory>
 
 #include "ash/common/shell_window_ids.h"
@@ skipping 192 matching lines @@
   void ShowResizeShadow(int component) override;
   void HideResizeShadow() override;
   void SetBoundsInScreenBehaviorForChildren(
       BoundsInScreenBehavior behavior) override;
   void SetSnapsChildrenToPhysicalPixelBoundary() override;
   void SnapToPixelBoundaryIfNecessary() override;
   void SetChildrenUseExtendedHitRegion() override;
   void SetDescendantsStayInSameRootWindow(bool value) override;
   void AddObserver(WmWindowObserver* observer) override;
   void RemoveObserver(WmWindowObserver* observer) override;
+  bool HasObserver(const WmWindowObserver* observer) const override;
 
  private:
   // mus::WindowObserver:
   void OnTreeChanging(const TreeChangeParams& params) override;
   void OnTreeChanged(const TreeChangeParams& params) override;
   void OnWindowReordered(::mus::Window* window,
                          ::mus::Window* relative_window,
                          ::mus::mojom::OrderDirection direction) override;
   void OnWindowSharedPropertyChanged(
       ::mus::Window* window,
@@ skipping 32 matching lines @@
   // resizing easier.
   bool children_use_extended_hit_region_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(WmWindowMus);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_