chromeos: Move files in //ash/common to //ash, part 3

chrome/browser/chromeos/arc/boot_phase_monitor/arc_instance_throttle.h

 // Copyright 2017 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 CHROME_BROWSER_CHROMEOS_ARC_BOOT_PHASE_MONITOR_ARC_INSTANCE_THROTTLE_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_BOOT_PHASE_MONITOR_ARC_INSTANCE_THROTTLE_H_
 
-#include "ash/common/wm_activation_observer.h"
+#include "ash/wm_activation_observer.h"
 #include "base/macros.h"
 
 namespace arc {
 
 // A class that watches window activations and prioritizes the ARC instance when
 // one of ARC windows is activated. The class also unprioritizes the instance
 // when non-ARC window such as Chrome is activated.
 class ArcInstanceThrottle : public ash::WmActivationObserver {
  public:
   ArcInstanceThrottle();
   ~ArcInstanceThrottle() override;
 
   // ash::WmActivationObserver overrides:
   void OnWindowActivated(ash::WmWindow* gained_active,
                          ash::WmWindow* lost_active) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ArcInstanceThrottle);
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_BOOT_PHASE_MONITOR_ARC_INSTANCE_THROTTLE_H_