Fix Volume slider is captured in screenshot done in touchview mode

ash/common/system/audio/tray_audio.h

 // Copyright 2014 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_COMMON_SYSTEM_AUDIO_TRAY_AUDIO_H_
 #define ASH_COMMON_SYSTEM_AUDIO_TRAY_AUDIO_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "ash/common/system/audio/audio_observer.h"
 #include "ash/common/system/tray/tray_image_item.h"
+#include "ash/common/wm/maximize_mode/maximize_mode_screenshot_observer.h"
 #include "base/macros.h"
 #include "ui/display/display_observer.h"
 
 namespace ash {
 
 namespace system {
 class TrayAudioDelegate;
 }
 
 namespace tray {
 class VolumeView;
 }
 
 class TrayAudio : public TrayImageItem,
                   public AudioObserver,
-                  public display::DisplayObserver {
+                  public display::DisplayObserver,
+                  public MaximizeModeScreenshotObserver {
  public:
   TrayAudio(SystemTray* system_tray,
             std::unique_ptr<system::TrayAudioDelegate> audio_delegate);
   ~TrayAudio() override;
 
   static bool ShowAudioDeviceMenu();
 
  protected:
   // Overridden from display::DisplayObserver.
   void OnDisplayAdded(const display::Display& new_display) override;
@@ skipping 22 matching lines @@
   bool ShouldHideArrow() const override;
   bool ShouldShowShelf() const override;
 
   // Overridden from AudioObserver.
   void OnOutputNodeVolumeChanged(uint64_t node_id, double volume) override;
   void OnOutputMuteChanged(bool mute_on, bool system_adjust) override;
   void OnAudioNodesChanged() override;
   void OnActiveOutputNodeChanged() override;
   void OnActiveInputNodeChanged() override;
 
+  // Overridden from MaximizeModeScreenshotObserver.
+  void OnWillTakeScreenshotInMaximizeMode() override;
+
   void ChangeInternalSpeakerChannelMode();
 
+  // Indicator if it is doing restoring volume after a maximize mode screenshot.
+  // If true, this volume set should not has popup view.
+  bool hide_popup_;
+
   DISALLOW_COPY_AND_ASSIGN(TrayAudio);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_AUDIO_TRAY_AUDIO_H_