arc: Revamp the ArcBridgeService interface

components/arc/window_manager/arc_window_manager_bridge.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 COMPONENTS_ARC_WINDOW_MANAGER_ARC_WINDOW_MANAGER_BRIDGE_H_
 #define COMPONENTS_ARC_WINDOW_MANAGER_ARC_WINDOW_MANAGER_BRIDGE_H_
 
 #include <string>
 
 #include "ash/common/shell_observer.h"
 #include "base/macros.h"
 #include "components/arc/arc_bridge_service.h"
 #include "components/arc/arc_service.h"
+#include "components/arc/instance_holder.h"
 
 namespace arc {
 
-class ArcWindowManagerBridge : public ArcService,
-                               public ArcBridgeService::Observer,
-                               public ash::ShellObserver {
+class ArcWindowManagerBridge
+    : public ArcService,
+      public InstanceHolder<mojom::WindowManagerInstance>::Observer,
+      public ash::ShellObserver {
  public:
   explicit ArcWindowManagerBridge(ArcBridgeService* bridge_service);
   ~ArcWindowManagerBridge() override;
 
-  // ArcBridgeService::Observer
-  void OnWindowManagerInstanceReady() override;
+  // InstanceHolder<mojom::WindowManagerInstance>::Observer
+  void OnInstanceReady() override;
 
   // Ash::Shell::ShellObserver
   void OnMaximizeModeStarted() override;
   void OnMaximizeModeEnded() override;
 
  private:
   void SendWindowManagerModeChange(bool touch_view_enabled);
 
   // Remembers the currently set mode on the Android side.
   mojom::WindowManagerMode current_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcWindowManagerBridge);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_WINDOW_MANAGER_ARC_WINDOW_MANAGER_BRIDGE_H_