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

webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.cc

Index: webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.cc
diff --git a/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.cc b/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.cc
index c70bf5e7a585f1528eda19a9326e3e9a6b9d0cef..ed81247aae37159cf3e60fe0b0db90607f64dca2 100644
--- a/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.cc
+++ b/webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.cc
@@ -51,9 +51,9 @@ void CovarianceMatrixGenerator::UniformCovarianceMatrix(
 void CovarianceMatrixGenerator::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) {
@@ -75,8 +75,8 @@ void CovarianceMatrixGenerator::AngledCovarianceMatrix(
 }
 
 void CovarianceMatrixGenerator::PhaseAlignmentMasks(
-    int frequency_bin,
-    int fft_size,
+    size_t frequency_bin,
+    size_t fft_size,
     int sample_rate,
     float sound_speed,
     const std::vector<Point>& geometry,