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

webrtc/common_audio/vad/vad_core_unittest.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 64 matching lines @@
     if (ValidRatesAndFrameLengths(32000, kFrameLengths[j])) {
       EXPECT_EQ(0, WebRtcVad_CalcVad32khz(self, speech, kFrameLengths[j]));
     }
     if (ValidRatesAndFrameLengths(48000, kFrameLengths[j])) {
       EXPECT_EQ(0, WebRtcVad_CalcVad48khz(self, speech, kFrameLengths[j]));
     }
   }
 
   // Construct a speech signal that will trigger the VAD in all modes. It is
   // known that (i * i) will wrap around, but that doesn't matter in this case.
-  for (int16_t i = 0; i < kMaxFrameLength; ++i) {
+  for (size_t i = 0; i < kMaxFrameLength; ++i) {
     speech[i] = static_cast<int16_t>(i * i);
   }
   for (size_t j = 0; j < kFrameLengthsSize; ++j) {
     if (ValidRatesAndFrameLengths(8000, kFrameLengths[j])) {
       EXPECT_EQ(1, WebRtcVad_CalcVad8khz(self, speech, kFrameLengths[j]));
     }
     if (ValidRatesAndFrameLengths(16000, kFrameLengths[j])) {
       EXPECT_EQ(1, WebRtcVad_CalcVad16khz(self, speech, kFrameLengths[j]));
     }
     if (ValidRatesAndFrameLengths(32000, kFrameLengths[j])) {
       EXPECT_EQ(1, WebRtcVad_CalcVad32khz(self, speech, kFrameLengths[j]));
     }
     if (ValidRatesAndFrameLengths(48000, kFrameLengths[j])) {
       EXPECT_EQ(1, WebRtcVad_CalcVad48khz(self, speech, kFrameLengths[j]));
     }
   }
 
   free(self);
 }
 }  // namespace