Fix Volume slider is captured in screenshot done in touchview mode

chromeos/audio/cras_audio_handler.h

 // Copyright (c) 2013 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 CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_
 #define CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <queue>
@@ skipping 141 matching lines @@
   virtual bool GetPrimaryActiveOutputDevice(AudioDevice* device) const;
 
   // Whether there is alternative input/output audio device.
   virtual bool has_alternative_input() const;
   virtual bool has_alternative_output() const;
 
   // Sets all active output devices' volume level to |volume_percent|, whose
   // range is from 0-100%.
   virtual void SetOutputVolumePercent(int volume_percent);
 
+  // Sets all active output devices' volume level to |volume_percent|, whose
+  // range is from 0-100% from internal sources, not users.
+  virtual void SetOutputVolumePercentInternally(int volume_percent);

[jennyz, 2016/07/28 21:02:17]

Sorry, the name is a little confusing here(my fault for suggesting it), since we
use SetXXXInternal in many other CrasAudioHandler function names, but it means
differently. Let's use a different name, such as
"SetOutputVolumePercentInQuietMode" or, maybe just add a bool |by_user| to
SetOutputVolumePercent. 

[Qiang(Joe) Xu, 2016/07/28 23:15:57]

Done.

+
   // Sets all active input devices' gain level to |gain_percent|, whose range is
   // from 0-100%.
   virtual void SetInputGainPercent(int gain_percent);
 
   // Adjusts all active output devices' volume up (positive percentage) or down
   // (negative percentage).
   virtual void AdjustOutputVolumeByPercent(int adjust_by_percent);
 
   // Adjusts all active output devices' volume to a minimum audible level if it
   // is too low.
@@ skipping 258 matching lines @@
   int hdmi_rediscover_grace_period_duration_in_ms_;
   bool hdmi_rediscovering_;
 
   bool cras_service_available_ = false;
 
   bool initializing_audio_state_ = false;
   int init_volume_;
   uint64_t init_node_id_;
   int init_volume_count_ = 0;
 
+  // True if volume change event is not coming from user-initiated operations.
+  bool volume_internally_changed_ = false;
+
   base::WeakPtrFactory<CrasAudioHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CrasAudioHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_