Support external audio mixer.

webrtc/media/engine/webrtcmediaengine_unittest.cc

Index: webrtc/media/engine/webrtcmediaengine_unittest.cc
diff --git a/webrtc/media/engine/webrtcmediaengine_unittest.cc b/webrtc/media/engine/webrtcmediaengine_unittest.cc
index 03e50a18c9a6dbaef712ea938647f398e7b4e963..b7a35dab631b598baa7278dd54ea21cebad5d223 100644
--- a/webrtc/media/engine/webrtcmediaengine_unittest.cc
+++ b/webrtc/media/engine/webrtcmediaengine_unittest.cc
@@ -182,13 +182,14 @@ TEST(WebRtcMediaEngineTest, FilterRtpExtensions_RemoveRedundantBwe_3) {
 
 TEST(WebRtcMediaEngineFactoryTest, CreateOldApi) {
   std::unique_ptr<MediaEngineInterface> engine(
-      WebRtcMediaEngineFactory::Create(nullptr, nullptr, nullptr));
+      WebRtcMediaEngineFactory::Create(nullptr, nullptr, nullptr, nullptr));
   EXPECT_TRUE(engine);
 }
 
 TEST(WebRtcMediaEngineFactoryTest, CreateWithBuiltinDecoders) {
   std::unique_ptr<MediaEngineInterface> engine(WebRtcMediaEngineFactory::Create(
-      nullptr, webrtc::CreateBuiltinAudioDecoderFactory(), nullptr, nullptr));
+      nullptr, webrtc::CreateBuiltinAudioDecoderFactory(), nullptr, nullptr,
+      nullptr));
   EXPECT_TRUE(engine);
 }