Move VideoFrame and related declarations to webrtc/api/video.

webrtc/common_video/libyuv/webrtc_libyuv.cc

Index: webrtc/common_video/libyuv/webrtc_libyuv.cc
diff --git a/webrtc/common_video/libyuv/webrtc_libyuv.cc b/webrtc/common_video/libyuv/webrtc_libyuv.cc
index dd5863dac66ba963adde40bc5e6324e02d99cde6..d64c9fc31407e2fdefe3fab9589b5247984f2802 100644
--- a/webrtc/common_video/libyuv/webrtc_libyuv.cc
+++ b/webrtc/common_video/libyuv/webrtc_libyuv.cc
@@ -16,6 +16,9 @@
 // NOTE(ajm): Path provided by gyp.

[the sun, 2016/11/24 10:36:59]

This comment is wrong

[nisse-webrtc, 2016/11/25 08:58:02]

Edited s/gyp/gn/.

BTW, I don't quite like the special handling of libyuv include paths in the
build files. It's needed for two reasons:

1. Internal includes of libyuv require it (which I find wrong, but we couldn't
reach agreement to land the fix in https://codereview.chromium.org/1977813002/).

2. We might want to support building webrtc with an out-of-tree libyuv, e.g.,
with headers installed in /usr/include.

 #include "libyuv.h"  // NOLINT
 
+// TODO(nisse): Only needed for the deprecated ConvertToI420.
+#include "webrtc/common_video/include/video_frame_buffer.h"
+
 namespace webrtc {
 
 VideoType RawVideoTypeToCommonVideoVideoType(RawVideoType type) {