Move videosinkinterface.h to common_video to solve a circular dep.

I updated some dependency enforcement rules to allow examples and pc
to depend on common_video. I reckoned depending on common_video is
not controversial when they already dependend on media/base, which
is a lower-level abstraction.

Bug: webrtc:6828
Change-Id: I77dbeb10187b4e70dda1d873a29994fa76070758
Reviewed-on: https://webrtc-review.googlesource.com/34187
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Commit-Queue: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21495}
diff --git a/api/mediastreaminterface.h b/api/mediastreaminterface.h
index 1699e4c..1350b29 100644
--- a/api/mediastreaminterface.h
+++ b/api/mediastreaminterface.h
@@ -27,7 +27,7 @@
 // TODO(zhihuang): Remove unrelated headers once downstream applications stop
 // relying on them; they were previously transitively included by
 // mediachannel.h, which is no longer a dependency of this file.
-#include "media/base/videosinkinterface.h"
+#include "api/videosinkinterface.h"
 #include "media/base/videosourceinterface.h"
 #include "modules/audio_processing/include/audio_processing_statistics.h"
 #include "rtc_base/ratetracker.h"