Add unit tests for webrtc_media_stream_adapter.cc

content/renderer/media/mock_media_stream_registry.h

Index: content/renderer/media/mock_media_stream_registry.h
diff --git a/content/renderer/media/mock_media_stream_registry.h b/content/renderer/media/mock_media_stream_registry.h
index 37c55ae67f320a1a2c2b6c5e589cd205c3a859a4..376646046046584ca97c84b2f3d2e6ca13d64852 100644
--- a/content/renderer/media/mock_media_stream_registry.h
+++ b/content/renderer/media/mock_media_stream_registry.h
@@ -9,6 +9,10 @@
 
 #include "content/renderer/media/media_stream_registry_interface.h"
 
+namespace blink {
+class WebMediaConstraints;
+}
+
 namespace content {
 
 // This class encapsulates creation of a Blink MediaStream having inside the
@@ -19,6 +23,8 @@ class MockMediaStreamRegistry final : public MediaStreamRegistryInterface {
   MockMediaStreamRegistry();
 
   void Init(const std::string& stream_url);
+  void AddVideoTrack(const std::string& track_id,
+                     const blink::WebMediaConstraints& constraints);
   void AddVideoTrack(const std::string& track_id);
   void AddAudioTrack(const std::string& track_id);
   blink::WebMediaStream GetMediaStream(const std::string& url) override;