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 0e4bb61e379addbd7b9cf7477712d47333959517..d5ba99409082a6778956abdf793543aa7dce14fe 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;
+}