Fix Volume slider is captured in screenshot done in touchview mode

chromeos/audio/cras_audio_handler.h

Index: chromeos/audio/cras_audio_handler.h
diff --git a/chromeos/audio/cras_audio_handler.h b/chromeos/audio/cras_audio_handler.h
index c9110718e4a332a7bc0dde2b5a02d446857a8e2f..fc412ba1b7ae7056573a335ae9697096bc83c6ca 100644
--- a/chromeos/audio/cras_audio_handler.h
+++ b/chromeos/audio/cras_audio_handler.h
@@ -159,6 +159,10 @@ class CHROMEOS_EXPORT CrasAudioHandler : public CrasAudioClient::Observer,
   // 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);
@@ -437,6 +441,9 @@ class CHROMEOS_EXPORT CrasAudioHandler : public CrasAudioClient::Observer,
   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);