[NOT FOR REVIEW] Convert channel counts to size_t.

webrtc/modules/audio_processing/echo_control_mobile_impl.cc

Index: webrtc/modules/audio_processing/echo_control_mobile_impl.cc
diff --git a/webrtc/modules/audio_processing/echo_control_mobile_impl.cc b/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
index 8d5ec9c4e296371672cefe50c4035a153280cd68..97368815395e123db960f0d516ae85de6ada97a1 100644
--- a/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
+++ b/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
@@ -90,8 +90,8 @@ int EchoControlMobileImpl::ProcessRenderAudio(const AudioBuffer* audio) {
 
   // The ordering convention must be followed to pass to the correct AECM.
   size_t handle_index = 0;
-  for (int i = 0; i < apm_->num_output_channels(); i++) {
-    for (int j = 0; j < audio->num_channels(); j++) {
+  for (size_t i = 0; i < apm_->num_output_channels(); i++) {
+    for (size_t j = 0; j < audio->num_channels(); j++) {
       Handle* my_handle = static_cast<Handle*>(handle(handle_index));
       err = WebRtcAecm_BufferFarend(
           my_handle,
@@ -125,7 +125,7 @@ int EchoControlMobileImpl::ProcessCaptureAudio(AudioBuffer* audio) {
 
   // The ordering convention must be followed to pass to the correct AECM.
   size_t handle_index = 0;
-  for (int i = 0; i < audio->num_channels(); i++) {
+  for (size_t i = 0; i < audio->num_channels(); i++) {
     // TODO(ajm): improve how this works, possibly inside AECM.
     //            This is kind of hacked up.
     const int16_t* noisy = audio->low_pass_reference(i);
@@ -134,7 +134,7 @@ int EchoControlMobileImpl::ProcessCaptureAudio(AudioBuffer* audio) {
       noisy = clean;
       clean = NULL;
     }
-    for (int j = 0; j < apm_->num_reverse_channels(); j++) {
+    for (size_t j = 0; j < apm_->num_reverse_channels(); j++) {
       Handle* my_handle = static_cast<Handle*>(handle(handle_index));
       err = WebRtcAecm_Process(
           my_handle,
@@ -282,7 +282,7 @@ int EchoControlMobileImpl::ConfigureHandle(void* handle) const {
   return WebRtcAecm_set_config(static_cast<Handle*>(handle), config);
 }
 
-int EchoControlMobileImpl::num_handles_required() const {
+size_t EchoControlMobileImpl::num_handles_required() const {
   return apm_->num_output_channels() *
          apm_->num_reverse_channels();
 }