Revert of Delete deprecated and transitional stuff related to video frame refactoring.

webrtc/api/video/i420_buffer.cc

Index: webrtc/api/video/i420_buffer.cc
diff --git a/webrtc/api/video/i420_buffer.cc b/webrtc/api/video/i420_buffer.cc
index 32c73eac67de98c822bcb818642e1d7d5fa9799b..81f57898372365a5ffff51fe7c95af37782eff53 100644
--- a/webrtc/api/video/i420_buffer.cc
+++ b/webrtc/api/video/i420_buffer.cc
@@ -131,6 +131,17 @@
   return buffer;
 }
 
+// static
+rtc::scoped_refptr<VideoFrameBuffer> I420Buffer::Rotate(
+    rtc::scoped_refptr<VideoFrameBuffer> src,
+    VideoRotation rotation) {
+  if (rotation == webrtc::kVideoRotation_0) {
+    return src;
+  } else {
+    return Rotate(*src, rotation);
+  }
+}
+
 void I420Buffer::InitializeData() {
   memset(data_.get(), 0,
          I420DataSize(height_, stride_y_, stride_u_, stride_v_));