Add a NOTREACHED and uma stat when the audio callback fails

media/audio/mac/audio_low_latency_input_mac.cc

 // 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.
 
 #include "media/audio/mac/audio_low_latency_input_mac.h"
 
 #include <CoreServices/CoreServices.h>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/mac/mac_logging.h"
+#include "base/metrics/histogram.h"
 #include "media/audio/mac/audio_manager_mac.h"
 #include "media/base/audio_bus.h"
 #include "media/base/data_buffer.h"
 
 namespace media {
 
 // Number of blocks of buffers used in the |fifo_|.
 const int kNumberOfBlocksBufferInFifo = 2;
 
 static std::ostream& operator<<(std::ostream& os,
@@ skipping 467 matching lines @@
   if (!audio_input)
     return kAudioUnitErr_InvalidElement;
 
   // Receive audio from the AUHAL from the output scope of the Audio Unit.
   OSStatus result = AudioUnitRender(audio_input->audio_unit(),
                                     flags,
                                     time_stamp,
                                     bus_number,
                                     number_of_frames,
                                     audio_input->audio_buffer_list());
-  if (result)
+  if (result) {
+    UMA_HISTOGRAM_COUNTS("Media.AudioInputCbErrorMac", result);
+    NOTREACHED();
     return result;
+  }
 
   // Deliver recorded data to the consumer as a callback.
   return audio_input->Provide(number_of_frames,
                               audio_input->audio_buffer_list(),
                               time_stamp);
 }
 
 OSStatus AUAudioInputStream::Provide(UInt32 number_of_frames,
                                      AudioBufferList* io_data,
                                      const AudioTimeStamp* time_stamp) {
@@ skipping 159 matching lines @@
     kAudioDevicePropertyScopeInput,
     static_cast<UInt32>(channel)
   };
   OSStatus result = AudioObjectIsPropertySettable(input_device_id_,
                                                   &property_address,
                                                   &is_settable);
   return (result == noErr) ? is_settable : false;
 }
 
 }  // namespace media