Introduce struct MediaConfig, with construction-time settings.

talk/app/webrtc/peerconnectioninterface_unittest.cc

 /*
  * libjingle
  * Copyright 2012 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 2337 matching lines @@
       webrtc::CreateSessionDescription(SessionDescriptionInterface::kOffer, sdp,
                                        nullptr));
 
   EXPECT_TRUE(DoSetLocalDescription(updated_desc.release()));
   senders = pc_->GetSenders();
   EXPECT_EQ(2u, senders.size());
   EXPECT_TRUE(ContainsSender(senders, kAudioTracks[0]));
   EXPECT_TRUE(ContainsSender(senders, kVideoTracks[0]));
 }
 
+class PeerConnectionFactoryForTest : public webrtc::PeerConnectionFactory {
+ public:
+  webrtc::MediaControllerInterface* CreateMediaController(
+      const cricket::MediaConfig &config) const override {
+    createmediacontroller_called = true;
+    createmediacontroller_config = config;
+
+    webrtc::MediaControllerInterface* mc =
+        PeerConnectionFactory::CreateMediaController(config);
+    EXPECT_TRUE(mc != nullptr);
+    return mc;
+  }
+
+  mutable bool createmediacontroller_called = false;

[pbos-webrtc, 2016/02/09 15:31:43]

create_media_controller_called

[perkj_webrtc, 2016/02/09 15:35:37]

member variables should end with _, iereatemediacontroller_called_

[perkj_webrtc, 2016/02/09 15:35:37]

why mutable  ?

[nisse-webrtc, 2016/02/10 08:53:00]

The CreateMediaController method is const. So I need to cheat to be able to
modify those members. One alternative is to move the variables out to a separate
struct and keep a reference to them, but using mutable seems simpler.

[nisse-webrtc, 2016/02/10 08:53:00]

Done.

[nisse-webrtc, 2016/02/10 08:53:00]

Done.

+  mutable cricket::MediaConfig createmediacontroller_config;

[perkj_webrtc, 2016/02/09 15:35:37]

dito

+};
+
+// This test verifies DSCP constraint is recognized and passed to the
+// CreateMediaController.
+TEST(PeerConnection, TestDscpConstraint) {

[pbos-webrtc, 2016/02/09 15:31:43]

Can you add tests for the other options as well? 

[nisse-webrtc, 2016/02/10 08:53:00]

I guess so. We just need to find the right balance. There are two constraints
which can be true, false or unset. And one flag copied from RTCConfiguration. So
a total of 18 combinations. 

I'm adding code to test a few selected combinations.

+  scoped_refptr<PeerConnectionFactoryForTest> pcf(
+      new rtc::RefCountedObject<PeerConnectionFactoryForTest>());
+  PeerConnectionInterface::RTCConfiguration config;
+  FakeConstraints constraints;
+  MockPeerConnectionObserver observer;

[perkj_webrtc, 2016/02/09 15:35:37]

move to where it is used.

+  scoped_refptr<PeerConnectionInterface> pc;

[perkj_webrtc, 2016/02/09 15:35:37]

declare when used.

+  constraints.AddOptional(
+      webrtc::MediaConstraintsInterface::kEnableDscp, true);

[perkj_webrtc, 2016/02/09 15:35:37]

also test calling with kEnableDscp false ?

+  pcf->Initialize();
+
+  EXPECT_FALSE(pcf->createmediacontroller_config.enable_dscp);
+
+  pc = pcf->CreatePeerConnection(config, &constraints,
+                                 nullptr, nullptr, &observer);
+  EXPECT_TRUE(pc.get() != nullptr);
+  EXPECT_TRUE(pcf->createmediacontroller_called);
+  EXPECT_TRUE(pcf->createmediacontroller_config.enable_dscp);
+}
+
 // The following tests verify that session options are created correctly.
 // TODO(deadbeef): Convert these tests to be more end-to-end. Instead of
 // "verify options are converted correctly", should be "pass options into
 // CreateOffer and verify the correct offer is produced."
 
 TEST(CreateSessionOptionsTest, GetOptionsForOfferWithInvalidAudioOption) {
   RTCOfferAnswerOptions rtc_options;
   rtc_options.offer_to_receive_audio = RTCOfferAnswerOptions::kUndefined - 1;
 
   cricket::MediaSessionOptions options;
@@ skipping 148 matching lines @@
   FakeConstraints updated_answer_c;
   answer_c.SetMandatoryReceiveAudio(false);
   answer_c.SetMandatoryReceiveVideo(false);
 
   cricket::MediaSessionOptions updated_answer_options;
   EXPECT_TRUE(
       ParseConstraintsForAnswer(&updated_answer_c, &updated_answer_options));
   EXPECT_TRUE(updated_answer_options.has_audio());
   EXPECT_TRUE(updated_answer_options.has_video());
 }