Convert channel counts to size_t.

webrtc/modules/audio_processing/beamformer/matrix_test_helpers.h

Index: webrtc/modules/audio_processing/beamformer/matrix_test_helpers.h
diff --git a/webrtc/modules/audio_processing/beamformer/matrix_test_helpers.h b/webrtc/modules/audio_processing/beamformer/matrix_test_helpers.h
index 7c5867006857214834a73d2c9aaf3873f7b601e0..9891a8220cbcacd8735c6e1d27f21f9c84180b0c 100644
--- a/webrtc/modules/audio_processing/beamformer/matrix_test_helpers.h
+++ b/webrtc/modules/audio_processing/beamformer/matrix_test_helpers.h
@@ -34,8 +34,8 @@ class MatrixTestHelpers {
 
     const T* const* expected_elements = expected.elements();
     const T* const* actual_elements = actual.elements();
-    for (int i = 0; i < expected.num_rows(); ++i) {
-      for (int j = 0; j < expected.num_columns(); ++j) {
+    for (size_t i = 0; i < expected.num_rows(); ++i) {
+      for (size_t j = 0; j < expected.num_columns(); ++j) {
         EXPECT_EQ(expected_elements[i][j], actual_elements[i][j]);
       }
     }
@@ -48,8 +48,8 @@ class MatrixTestHelpers {
 
     const float* const* expected_elements = expected.elements();
     const float* const* actual_elements = actual.elements();
-    for (int i = 0; i < expected.num_rows(); ++i) {
-      for (int j = 0; j < expected.num_columns(); ++j) {
+    for (size_t i = 0; i < expected.num_rows(); ++i) {
+      for (size_t j = 0; j < expected.num_columns(); ++j) {
         EXPECT_NEAR(expected_elements[i][j], actual_elements[i][j], kTolerance);
       }
     }
@@ -63,8 +63,8 @@ class MatrixTestHelpers {
 
     const complex<float>* const* expected_elements = expected.elements();
     const complex<float>* const* actual_elements = actual.elements();
-    for (int i = 0; i < expected.num_rows(); ++i) {
-      for (int j = 0; j < expected.num_columns(); ++j) {
+    for (size_t i = 0; i < expected.num_rows(); ++i) {
+      for (size_t j = 0; j < expected.num_columns(); ++j) {
         EXPECT_NEAR(expected_elements[i][j].real(),
                     actual_elements[i][j].real(),
                     kTolerance);
@@ -84,8 +84,8 @@ class MatrixTestHelpers {
 
     const complex<float>* const* expected_elements = expected.elements();
     const complex<float>* const* actual_elements = actual.elements();
-    for (int i = 0; i < expected.num_rows(); ++i) {
-      for (int j = 0; j < expected.num_columns(); ++j) {
+    for (size_t i = 0; i < expected.num_rows(); ++i) {
+      for (size_t j = 0; j < expected.num_columns(); ++j) {
         EXPECT_NEAR(expected_elements[i][j].real(),
                     actual_elements[i][j].real(),
                     tolerance);