Introduce struct MediaConfig, with construction-time settings.

webrtc/api/fakemediacontroller.h

Index: webrtc/api/fakemediacontroller.h
diff --git a/webrtc/api/fakemediacontroller.h b/webrtc/api/fakemediacontroller.h
index 56af5cfe38e71af8b514c8dd9084afec956a19cb..2e539e813aa431f6538060a768a30bb132a45843 100644
--- a/webrtc/api/fakemediacontroller.h
+++ b/webrtc/api/fakemediacontroller.h
@@ -13,6 +13,7 @@
 
 #include "webrtc/api/mediacontroller.h"
 #include "webrtc/base/checks.h"
+#include "webrtc/media/base/mediachannel.h"
 
 namespace cricket {
 
@@ -29,8 +30,10 @@ class FakeMediaController : public webrtc::MediaControllerInterface {
   cricket::ChannelManager* channel_manager() const override {
     return channel_manager_;
   }
+  const MediaConfig& config() const override { return media_config_; }
 
  private:
+  const MediaConfig media_config_ = MediaConfig();
   cricket::ChannelManager* channel_manager_;
   webrtc::Call* call_;
 };