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

webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.h

Index: webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.h
diff --git a/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.h b/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.h
index 5979462751bf9e5734255982a8900857f38907cf..5375518e8aabe3ace865667950aff6b2c332859d 100644
--- a/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.h
+++ b/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.h
@@ -30,9 +30,9 @@ class CovarianceMatrixGenerator {
   // The covariance matrix of a source at the given angle.
   static void AngledCovarianceMatrix(float sound_speed,
                                      float angle,
-                                     int frequency_bin,
-                                     int fft_size,
-                                     int num_freq_bins,
+                                     size_t frequency_bin,
+                                     size_t fft_size,
+                                     size_t num_freq_bins,
                                      int sample_rate,
                                      const std::vector<Point>& geometry,
                                      ComplexMatrix<float>* mat);
@@ -40,8 +40,8 @@ class CovarianceMatrixGenerator {
   // Calculates phase shifts that, when applied to a multichannel signal and
   // added together, cause constructive interferernce for sources located at
   // the given angle.
-  static void PhaseAlignmentMasks(int frequency_bin,
-                                  int fft_size,
+  static void PhaseAlignmentMasks(size_t frequency_bin,
+                                  size_t fft_size,
                                   int sample_rate,
                                   float sound_speed,
                                   const std::vector<Point>& geometry,