Update a ton of audio code to use size_t more correctly and in general reduce

webrtc/common_audio/window_generator.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 28 matching lines @@
 
 void WindowGenerator::Hanning(int length, float* window) {
   CHECK_GT(length, 1);
   CHECK(window != nullptr);
   for (int i = 0; i < length; ++i) {
     window[i] = 0.5f * (1 - cosf(2 * static_cast<float>(M_PI) * i /
                                  (length - 1)));
   }
 }
 
-void WindowGenerator::KaiserBesselDerived(float alpha, int length,
+void WindowGenerator::KaiserBesselDerived(float alpha, size_t length,
                                           float* window) {
-  CHECK_GT(length, 1);
+  CHECK_GT(length, 1U);
   CHECK(window != nullptr);
 
-  const int half = (length + 1) / 2;
+  const size_t half = (length + 1) / 2;
   float sum = 0.0f;
 
-  for (int i = 0; i <= half; ++i) {
+  for (size_t i = 0; i <= half; ++i) {
     complex<float> r = (4.0f * i) / length - 1.0f;
     sum += I0(static_cast<float>(M_PI) * alpha * sqrt(1.0f - r * r)).real();
     window[i] = sum;
   }
-  for (int i = length - 1; i >= half; --i) {
+  for (size_t i = length - 1; i >= half; --i) {
     window[length - i - 1] = sqrtf(window[length - i - 1] / sum);
     window[i] = window[length - i - 1];
   }
   if (length % 2 == 1) {
     window[half - 1] = sqrtf(window[half - 1] / sum);
   }
 }
 
 }  // namespace webrtc