Fixes crash in AudioInputVolumeTest.InputVolumeTest

media/audio/agc_audio_stream.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 MEDIA_AUDIO_AGC_AUDIO_STREAM_H_
 #define MEDIA_AUDIO_AGC_AUDIO_STREAM_H_
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
@@ skipping 131 matching lines @@
   // Gets the current automatic gain control state.
   virtual bool GetAutomaticGainControl() OVERRIDE {
     DCHECK(thread_checker_.CalledOnValidThread());
     return agc_is_enabled_;
   }
 
   // Takes a new microphone volume sample and stores it in |normalized_volume_|.
   // Range is normalized to [0.0,1.0] or [0.0, 1.5] on Linux.
   void QueryAndStoreNewMicrophoneVolume() {
     DCHECK(thread_checker_.CalledOnValidThread());
-    DCHECK(timer_.IsRunning());
+
+    // Avoid updating the volume member if AGC is not running.
+    if (!timer_.IsRunning())
+      return;
 
     // Cach the maximum volume if this is the first time we ask for it.
     if (max_volume_ == 0.0)
       max_volume_ = static_cast<AudioInterface*>(this)->GetMaxVolume();
 
     // Retrieve the current volume level by asking the audio hardware.
     // Range is normalized to [0.0,1.0] or [0.0, 1.5] on Linux.
     if (max_volume_ != 0.0) {
       double normalized_volume =
           static_cast<AudioInterface*>(this)->GetVolume() / max_volume_;
@@ skipping 33 matching lines @@
 
   // Protects |normalized_volume_| .
   base::Lock lock_;
 
   DISALLOW_COPY_AND_ASSIGN(AgcAudioStream<AudioInterface>);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AGC_AUDIO_STREAM_H_