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

webrtc/modules/utility/source/audio_frame_operations_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 10 matching lines @@
   AudioFrameOperationsTest() {
     // Set typical values.
     frame_.samples_per_channel_ = 320;
     frame_.num_channels_ = 2;
   }
 
   AudioFrame frame_;
 };
 
 void SetFrameData(AudioFrame* frame, int16_t left, int16_t right) {
-  for (int i = 0; i < frame->samples_per_channel_ * 2; i += 2) {
+  for (size_t i = 0; i < frame->samples_per_channel_ * 2; i += 2) {
     frame->data_[i] = left;
     frame->data_[i + 1] = right;
   }
 }
 
 void SetFrameData(AudioFrame* frame, int16_t data) {
-  for (int i = 0; i < frame->samples_per_channel_; i++) {
+  for (size_t i = 0; i < frame->samples_per_channel_; i++) {
     frame->data_[i] = data;
   }
 }
 
 void VerifyFramesAreEqual(const AudioFrame& frame1, const AudioFrame& frame2) {
   EXPECT_EQ(frame1.num_channels_, frame2.num_channels_);
   EXPECT_EQ(frame1.samples_per_channel_,
             frame2.samples_per_channel_);
 
-  for (int i = 0; i < frame1.samples_per_channel_ * frame1.num_channels_;
+  for (size_t i = 0; i < frame1.samples_per_channel_ * frame1.num_channels_;
       i++) {
     EXPECT_EQ(frame1.data_[i], frame2.data_[i]);
   }
 }
 
 TEST_F(AudioFrameOperationsTest, MonoToStereoFailsWithBadParameters) {
   EXPECT_EQ(-1, AudioFrameOperations::MonoToStereo(&frame_));
 
   frame_.samples_per_channel_ = AudioFrame::kMaxDataSizeSamples;
   frame_.num_channels_ = 1;
@@ skipping 157 matching lines @@
 
   AudioFrame scaled_frame;
   scaled_frame.samples_per_channel_ = 320;
   scaled_frame.num_channels_ = 1;
   SetFrameData(&scaled_frame, 2);
   VerifyFramesAreEqual(scaled_frame, frame_);
 }
 
 }  // namespace
 }  // namespace webrtc