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

webrtc/common_audio/vad/vad.cc

Index: webrtc/common_audio/vad/vad.cc
diff --git a/webrtc/common_audio/vad/vad.cc b/webrtc/common_audio/vad/vad.cc
index fd09c3f7f9fbd5d72b93840097a9d2e11fd30cfa..764d024cbd36a0abd7bcc9a7cee6ca5ff61d6bae 100644
--- a/webrtc/common_audio/vad/vad.cc
+++ b/webrtc/common_audio/vad/vad.cc
@@ -28,8 +28,7 @@ Vad::~Vad() {
 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;