Add AudioSendStream::SetMuted() method and use it in WVoMC::MuteStream().

webrtc/audio/audio_send_stream_unittest.cc

Index: webrtc/audio/audio_send_stream_unittest.cc
diff --git a/webrtc/audio/audio_send_stream_unittest.cc b/webrtc/audio/audio_send_stream_unittest.cc
index 44392ea1c0edb6238e83564cfd51fa84329cd11b..b9535543e23661891b4594350b1ccae3f9b7bd89 100644
--- a/webrtc/audio/audio_send_stream_unittest.cc
+++ b/webrtc/audio/audio_send_stream_unittest.cc
@@ -110,6 +110,7 @@ struct ConfigHelper {
 
   AudioSendStream::Config& config() { return stream_config_; }
   rtc::scoped_refptr<AudioState> audio_state() { return audio_state_; }
+  MockVoEChannelProxy* channel_proxy() { return channel_proxy_; }
   CongestionController* congestion_controller() {
     return &congestion_controller_;
   }
@@ -200,6 +201,14 @@ TEST(AudioSendStreamTest, SendTelephoneEvent) {
       kTelephoneEventCode, kTelephoneEventDuration));
 }
 
+TEST(AudioSendStreamTest, SetMuted) {
+  ConfigHelper helper;
+  internal::AudioSendStream send_stream(helper.config(), helper.audio_state(),
+                                        helper.congestion_controller());
+  EXPECT_CALL(*helper.channel_proxy(), SetInputMute(true));
+  send_stream.SetMuted(true);
+}
+
 TEST(AudioSendStreamTest, GetStats) {
   ConfigHelper helper;
   internal::AudioSendStream send_stream(helper.config(), helper.audio_state(),