Fix mistake in dummy videotracksource.cc and h
VideoTrackSource will be implemented in an upcoming cl but is needed to be included in libjingle.gyp in Chrome before the cl can be landed.

R=kjellander@webrtc.org

Review URL: https://codereview.webrtc.org/1769343003 .

Cr-Commit-Position: refs/heads/master@{#11897}
diff --git a/webrtc/api/api.gyp b/webrtc/api/api.gyp
index 1e32e36..d97c38b 100644
--- a/webrtc/api/api.gyp
+++ b/webrtc/api/api.gyp
@@ -315,6 +315,8 @@
         'videotrack.h',
         'videotrackrenderers.cc',
         'videotrackrenderers.h',
+        'videotracksource.cc',
+        'videotracksource.h',
         'webrtcsdp.cc',
         'webrtcsdp.h',
         'webrtcsession.cc',