Add PeerConnectionInterface::UpdateCallBitrate with call tests.

webrtc/media/engine/fakewebrtccall.cc

Index: webrtc/media/engine/fakewebrtccall.cc
diff --git a/webrtc/media/engine/fakewebrtccall.cc b/webrtc/media/engine/fakewebrtccall.cc
index b53966586f8302723eb3b00da13eab77c9610d86..8bc98a0f947b900db0100de9777dc7922d17ddc3 100644
--- a/webrtc/media/engine/fakewebrtccall.cc
+++ b/webrtc/media/engine/fakewebrtccall.cc
@@ -583,6 +583,12 @@ void FakeCall::SetBitrateConfig(
   config_.bitrate_config = bitrate_config;
 }
 
+webrtc::RTCError FakeCall::SetBitrateConfigMask(
+    const webrtc::Call::Config::BitrateConfigMask& mask) {
+  // TODO(zstein): not implemented
+  return webrtc::RTCError::OK();
+}
+
 void FakeCall::SignalChannelNetworkState(webrtc::MediaType media,
                                          webrtc::NetworkState state) {
   switch (media) {