Introduce struct MediaConfig, with construction-time settings.

talk/app/webrtc/webrtcsession_unittest.cc

Index: talk/app/webrtc/webrtcsession_unittest.cc
diff --git a/talk/app/webrtc/webrtcsession_unittest.cc b/talk/app/webrtc/webrtcsession_unittest.cc
index c553165f9b57f523e965d3d82efbee3fb37461b2..4e6732f2968b14df3c15c96e03757a371e6c8de4 100644
--- a/talk/app/webrtc/webrtcsession_unittest.cc
+++ b/talk/app/webrtc/webrtcsession_unittest.cc
@@ -364,6 +364,7 @@ class WebRtcSessionTest
         fake_call_(webrtc::Call::Config()),
         media_controller_(
             webrtc::MediaControllerInterface::Create(rtc::Thread::Current(),
+                                                     webrtc::MediaConfig(),
                                                      channel_manager_.get())),
         tdesc_factory_(new cricket::TransportDescriptionFactory()),
         desc_factory_(
@@ -4074,7 +4075,10 @@ TEST_F(WebRtcSessionTest, TestSetRemoteOfferFailIfDtlsDisabledAndNoCrypto) {
 }
 
 // This test verifies DSCP is properly applied on the media channels.
-TEST_F(WebRtcSessionTest, TestDscpConstraint) {
+// TODO(nisse): Test needs refactoring, see cl
+// https://codereview.webrtc.org/1646253004
+TEST_F(WebRtcSessionTest, DISABLED_TestDscpConstraint) {
+#if 0

[pthatcher1, 2016/02/05 17:11:30]

Are you going to fix this in this CL?

[nisse-webrtc, 2016/02/08 09:02:32]

Yes. I think the previous cl (https://codereview.webrtc.org/1646253004/)
includes the needed changes, patchset 4, I just have to move it over.

The plan is to use FakeNetworkInterface and check the dscp property there, and
not use the options() method. 

(I'd actually prefer to delete the options() method, SetOptions should be able
to apply options in any way it needs without keeping a literal copy, but that's
unrelated to this cl).

[nisse-webrtc, 2016/02/08 12:22:30]

I'm getting into trouble with the webrtcsession unittests.

Problem is, the MediaController is created by PeerConnection::Initialize. So
populating MediaConfig, and looking for the corresponding constraints, is moved
to this method. After creating the MediaController, it creates a WebRtcSession
and passes the MediaController to it.

But in WebRtcSessionTest.TestDscpConstraint, there's no PeerConnection involved,
and hence the code to handle the constraint, in PeerConnection::Initialize,
simply has no place in the test. I guess the sanest solution is to somehow move
this test to the peerconnection unittests?

[pthatcher1, 2016/02/08 19:03:01]

I agree that the right thing to do is move it to peerconnection unittests.

   constraints_.reset(new FakeConstraints());
   constraints_->AddOptional(
       webrtc::MediaConstraintsInterface::kEnableDscp, true);
@@ -4093,6 +4097,7 @@ TEST_F(WebRtcSessionTest, TestDscpConstraint) {
   const cricket::VideoOptions& video_options = video_channel_->options();
   EXPECT_EQ(rtc::Optional<bool>(true), audio_options.dscp);
   EXPECT_EQ(rtc::Optional<bool>(true), video_options.dscp);
+#endif
 }
 
 TEST_F(WebRtcSessionTest, TestSuspendBelowMinBitrateConstraint) {