Interface for requestSources through UserMediaController/Client.

Source/web/UserMediaClientImpl.cpp

Index: Source/web/UserMediaClientImpl.cpp
diff --git a/Source/web/UserMediaClientImpl.cpp b/Source/web/UserMediaClientImpl.cpp
index ee0804e1eb1c69266d6808703ebee7bc5e0d3119..cb77c32e116187b41bc5c16537eda6824fa96877 100644
--- a/Source/web/UserMediaClientImpl.cpp
+++ b/Source/web/UserMediaClientImpl.cpp
@@ -31,6 +31,7 @@
 #include "config.h"
 #include "web/UserMediaClientImpl.h"
 
+#include "public/platform/WebMediaStreamTrackSourcesRequest.h"
 #include "public/web/WebFrameClient.h"
 #include "public/web/WebMediaDevicesRequest.h"
 #include "public/web/WebUserMediaClient.h"
@@ -69,4 +70,10 @@ void UserMediaClientImpl::cancelMediaDevicesRequest(MediaDevicesRequest* request
         m_client->cancelMediaDevicesRequest(WebMediaDevicesRequest(request));
 }
 
+void UserMediaClientImpl::requestSources(MediaStreamTrackSourcesRequest* request)
+{
+    if (m_client)
+        m_client->requestSources(request);
+}
+
 } // namespace blink