Match existing type usage better.

webrtc/modules/audio_device/audio_device_buffer.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 545 matching lines @@
                                                      &_playBuffer[0],
                                                      nSamplesOut,
                                                      &elapsed_time_ms,
                                                      &ntp_time_ms);
         if (res != 0)
         {
             WEBRTC_TRACE(kTraceError, kTraceAudioDevice, _id, "NeedMorePlayData() failed");
         }
     }
 
-    return nSamplesOut;
+    return static_cast<int32_t>(nSamplesOut);
 }
 
 // ----------------------------------------------------------------------------
 //  GetPlayoutData
 // ----------------------------------------------------------------------------
 
 int32_t AudioDeviceBuffer::GetPlayoutData(void* audioBuffer)
 {
     CriticalSectionScoped lock(&_critSect);
 
     if (_playSize > kMaxBufferSizeBytes)
     {
        WEBRTC_TRACE(kTraceError, kTraceUtility, _id, "_playSize %i exceeds "
        "kMaxBufferSizeBytes in AudioDeviceBuffer::GetPlayoutData", _playSize);
        assert(false);
        return -1;
     }
 
     memcpy(audioBuffer, &_playBuffer[0], _playSize);
 
     if (_playFile.Open())
     {
         // write to binary file in mono or stereo (interleaved)
         _playFile.Write(&_playBuffer[0], _playSize);
     }
 
-    return _playSamples;
+    return static_cast<int32_t>(_playSamples);
 }
 
 }  // namespace webrtc