Update audio code to use size_t more correctly, webrtc/common_audio/ portion.

webrtc/common_audio/vad/vad.cc

 /*
  *  Copyright (c) 2014 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 10 matching lines @@
   CHECK_EQ(WebRtcVad_set_mode(handle_, mode), 0);
 }
 
 Vad::~Vad() {
   WebRtcVad_Free(handle_);
 }
 
 enum Vad::Activity Vad::VoiceActivity(const int16_t* audio,
                                       size_t num_samples,
                                       int sample_rate_hz) {
-  int ret = WebRtcVad_Process(
-      handle_, sample_rate_hz, audio, static_cast<int>(num_samples));
+  int ret = WebRtcVad_Process(handle_, sample_rate_hz, audio, num_samples);
   switch (ret) {
     case 0:
       return kPassive;
     case 1:
       return kActive;
     default:
       DCHECK(false) << "WebRtcVad_Process returned an error.";
       return kError;
   }
 }
 
 }  // namespace webrtc