Introduce struct MediaConfig, with construction-time settings.

webrtc/media/base/videoengine_unittest.h

Index: webrtc/media/base/videoengine_unittest.h
diff --git a/webrtc/media/base/videoengine_unittest.h b/webrtc/media/base/videoengine_unittest.h
index 8a372a35be69fa81f42dbdede7f5a123f9eea7c1..6ee61efa36416ed0552cd44b9ef005315b2a86e8 100644
--- a/webrtc/media/base/videoengine_unittest.h
+++ b/webrtc/media/base/videoengine_unittest.h
@@ -110,8 +110,9 @@ class VideoMediaChannelTest : public testing::Test,
   virtual void SetUp() {
     cricket::Device device("test", "device");
     engine_.Init();
-    channel_.reset(
-        engine_.CreateChannel(call_.get(), cricket::VideoOptions()));
+    channel_.reset(engine_.CreateChannel(call_.get(),
+                                         cricket::MediaConfig(),
+                                         cricket::VideoOptions()));
     EXPECT_TRUE(channel_.get() != NULL);
     network_interface_.SetDestination(channel_.get());
     channel_->SetInterface(&network_interface_);