Make cricket::VideoFrame inherit webrtc::VideoFrame.

webrtc/media/engine/webrtcvideoengine2.h

Index: webrtc/media/engine/webrtcvideoengine2.h
diff --git a/webrtc/media/engine/webrtcvideoengine2.h b/webrtc/media/engine/webrtcvideoengine2.h
index 7e32116608c7e87f572c201e3485f74cf558d8ab..1061c6556cc4eca103c07cc8a088b16cffcb76e3 100644
--- a/webrtc/media/engine/webrtcvideoengine2.h
+++ b/webrtc/media/engine/webrtcvideoengine2.h
@@ -26,6 +26,7 @@
 #include "webrtc/media/base/videosourceinterface.h"
 #include "webrtc/call.h"
 #include "webrtc/media/base/mediaengine.h"
+#include "webrtc/media/base/videoframe.h"
 #include "webrtc/media/engine/webrtcvideochannelfactory.h"
 #include "webrtc/media/engine/webrtcvideodecoderfactory.h"
 #include "webrtc/media/engine/webrtcvideoencoderfactory.h"
@@ -47,7 +48,11 @@ class Thread;
 namespace cricket {
 
 class VideoCapturer;
+// TODO(nisse): For some reason, forward declaration doens't work when
+// the definition is a "using" alias.
+#if 0
 class VideoFrame;
+#endif
 class VideoProcessor;
 class VideoRenderer;
 class VoiceMediaChannel;
@@ -60,7 +65,6 @@ class WebRtcVideoChannelSendInfo;
 class WebRtcVoiceEngine;
 class WebRtcVoiceMediaChannel;
 
-struct CapturedFrame;
 struct Device;
 
 // Exposed here for unittests.