Introduce struct MediaConfig, with construction-time settings.

talk/app/webrtc/fakemediacontroller.h

Index: talk/app/webrtc/fakemediacontroller.h
diff --git a/talk/app/webrtc/fakemediacontroller.h b/talk/app/webrtc/fakemediacontroller.h
index 5bf3e5fcf8556b914436c948d887468241ae2fae..f65a8aa05703cd2eda6b62e331a837f381237b14 100644
--- a/talk/app/webrtc/fakemediacontroller.h
+++ b/talk/app/webrtc/fakemediacontroller.h
@@ -30,6 +30,7 @@
 
 #include "talk/app/webrtc/mediacontroller.h"
 #include "webrtc/base/checks.h"
+#include "webrtc/media/base/mediachannel.h"
 
 namespace cricket {
 
@@ -46,8 +47,12 @@ 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_;
 };