Consolidate volume control code.

ash/system/tray/system_tray_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 ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 
 #include <string>
 #include <vector>
 
 #include "ash/ash_export.h"
 #include "ash/system/power/power_supply_status.h"
 #include "ash/system/user/login_status.h"
 #include "base/file_path.h"
 #include "base/i18n/time_formatting.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/string16.h"
 #include "ui/gfx/image/image_skia.h"
 
 namespace ash {
 
 struct ASH_EXPORT NetworkIconInfo {
   NetworkIconInfo();
   ~NetworkIconInfo();
 
   bool highlight;
@@ skipping 63 matching lines @@
 
   bool selected;
   bool third_party;
   std::string id;
   string16 name;
   string16 short_name;
 };
 
 typedef std::vector<IMEInfo> IMEInfoList;
 
+class VolumeControlDelegate;
+
 class SystemTrayDelegate {
  public:
   virtual ~SystemTrayDelegate() {}
 
   // Returns true if system tray should be visible on startup.
   virtual bool GetTrayVisibilityOnStartup() = 0;
 
   // Gets information about the logged in user.
   virtual const string16 GetUserDisplayName() const = 0;
   virtual const std::string GetUserEmail() const = 0;
@@ skipping 26 matching lines @@
 
   // Shows settings related to Google Drive.
   virtual void ShowDriveSettings() = 0;
 
   // Shows settings related to input methods.
   virtual void ShowIMESettings() = 0;
 
   // Shows help.
   virtual void ShowHelp() = 0;
 
-  // Is the system audio muted?
-  virtual bool IsAudioMuted() const = 0;
-
-  // Mutes/Unmutes the audio system.
-  virtual void SetAudioMuted(bool muted) = 0;
-
-  // Gets the volume level. The range is [0, 1.0].
-  virtual float GetVolumeLevel() const = 0;
-
-  // Sets the volume level. The range is [0, 1.0].
-  virtual void SetVolumeLevel(float level) = 0;
-
   // Gets whether the caps lock is on.
   virtual bool IsCapsLockOn() const = 0;
 
   // Sets the caps lock status to |enabled|.
   virtual void SetCapsLockEnabled(bool enabled) = 0;
 
   // Attempts to shut down the system.
   virtual void ShutDown() = 0;
 
   // Attempts to sign out the user.
@@ skipping 104 matching lines @@
   // Note: |setup_url| is returned when carrier is not defined (no SIM card).
   virtual bool GetCellularCarrierInfo(std::string* carrier_id,
                                       std::string* topup_url,
                                       std::string* setup_url) = 0;
 
   // Opens the cellular network specific URL.
   virtual void ShowCellularURL(const std::string& url) = 0;
 
   // Shows UI for changing proxy settings.
   virtual void ChangeProxySettings() = 0;
+
+  // Returns VolumeControlDelegate.
+  virtual VolumeControlDelegate* GetVolumeControlDelegate() const = 0;
+
+  // Sets VolumeControlDelegate.
+  virtual void SetVolumeControlDelegate(
+      scoped_ptr<VolumeControlDelegate> delegate) = 0;
+
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_