Adds Analog Gain Control (AGC) to the WebRTC client.

media/audio/fake_audio_input_stream.cc

Index: media/audio/fake_audio_input_stream.cc
diff --git a/media/audio/fake_audio_input_stream.cc b/media/audio/fake_audio_input_stream.cc
index f1284f1acb3f412c1c805092c723d348557020a3..c4d9a09c216803dd6c1e2d11ba811e80e0aad81b 100644
--- a/media/audio/fake_audio_input_stream.cc
+++ b/media/audio/fake_audio_input_stream.cc
@@ -48,7 +48,7 @@ void FakeAudioInputStream::Start(AudioInputCallback* callback)  {
 
 void FakeAudioInputStream::DoCallback() {
   DCHECK(callback_);
-  callback_->OnData(this, buffer_.get(), buffer_size_, buffer_size_);
+  callback_->OnData(this, buffer_.get(), buffer_size_, buffer_size_, 0.0);
 
   Time now = Time::Now();
   base::TimeDelta next_callback_time =
@@ -87,3 +87,9 @@ void FakeAudioInputStream::SetVolume(double volume) {}
 double FakeAudioInputStream::GetVolume() {
   return 0.0;
 }
+
+void FakeAudioInputStream::SetAutomaticGainControl(bool enabled) {}
+
+bool FakeAudioInputStream::GetAutomaticGainControl() {
+  return false;
+}