cros: Suspend media sessions with display off trigger by tablet power button

chrome/browser/ui/ash/chrome_shell_delegate.h

 // Copyright (c) 2012 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_UI_ASH_CHROME_SHELL_DELEGATE_H_
 #define CHROME_BROWSER_UI_ASH_CHROME_SHELL_DELEGATE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 43 matching lines @@
   ash::GPUSupport* CreateGPUSupport() override;
   base::string16 GetProductName() const override;
   void OpenKeyboardShortcutHelpPage() const override;
   gfx::Image GetDeprecatedAcceleratorImage() const override;
   PrefService* GetActiveUserPrefService() const override;
   bool IsTouchscreenEnabledInPrefs(bool use_local_state) const override;
   void SetTouchscreenEnabledInPrefs(bool enabled,
                                     bool use_local_state) override;
   void UpdateTouchscreenStatusFromPrefs() override;
   void ToggleTouchpad() override;
+  void ResumeMediaSessions() override;
+  void SuspendMediaSessions() override;
 
   // content::NotificationObserver override:
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
  private:
   void PlatformInit();
 
   content::NotificationRegistrar registrar_;
 
   std::unique_ptr<ChromeLauncherController> launcher_controller_;
 
   std::unique_ptr<chromeos::DisplayConfigurationObserver>
       display_configuration_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeShellDelegate);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_CHROME_SHELL_DELEGATE_H_