[NOT FOR REVIEW] Convert channel counts to size_t.

webrtc/common_audio/lapped_transform.cc

Index: webrtc/common_audio/lapped_transform.cc
diff --git a/webrtc/common_audio/lapped_transform.cc b/webrtc/common_audio/lapped_transform.cc
index 525450d0cfc6bdfd025177f1d6490f8da2015eeb..00421f5270ea739384d2f008280304aff0649f45 100644
--- a/webrtc/common_audio/lapped_transform.cc
+++ b/webrtc/common_audio/lapped_transform.cc
@@ -21,14 +21,14 @@ namespace webrtc {
 
 void LappedTransform::BlockThunk::ProcessBlock(const float* const* input,
                                                size_t num_frames,
-                                               int num_input_channels,
-                                               int num_output_channels,
+                                               size_t num_input_channels,
+                                               size_t num_output_channels,
                                                float* const* output) {
   CHECK_EQ(num_input_channels, parent_->num_in_channels_);
   CHECK_EQ(num_output_channels, parent_->num_out_channels_);
   CHECK_EQ(parent_->block_length_, num_frames);
 
-  for (int i = 0; i < num_input_channels; ++i) {
+  for (size_t i = 0; i < num_input_channels; ++i) {
     memcpy(parent_->real_buf_.Row(i), input[i],
            num_frames * sizeof(*input[0]));
     parent_->fft_->Forward(parent_->real_buf_.Row(i),
@@ -44,7 +44,7 @@ void LappedTransform::BlockThunk::ProcessBlock(const float* const* input,
                                                num_output_channels,
                                                parent_->cplx_post_.Array());
 
-  for (int i = 0; i < num_output_channels; ++i) {
+  for (size_t i = 0; i < num_output_channels; ++i) {
     parent_->fft_->Inverse(parent_->cplx_post_.Row(i),
                            parent_->real_buf_.Row(i));
     memcpy(output[i], parent_->real_buf_.Row(i),
@@ -52,8 +52,8 @@ void LappedTransform::BlockThunk::ProcessBlock(const float* const* input,
   }
 }
 
-LappedTransform::LappedTransform(int num_in_channels,
-                                 int num_out_channels,
+LappedTransform::LappedTransform(size_t num_in_channels,
+                                 size_t num_out_channels,
                                  size_t chunk_length,
                                  const float* window,
                                  size_t block_length,