Revert of Delete VideoFrame default constructor, and IsZeroSize method.

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 0bb592d73348c776d6eeda966af97c2847ae2603..6bfb1799ee12d5d6ff567ff0ea83f3301982d304 100644
--- a/webrtc/common_video/libyuv/webrtc_libyuv.cc
+++ b/webrtc/common_video/libyuv/webrtc_libyuv.cc
@@ -128,6 +128,8 @@
 }
 
 int PrintVideoFrame(const VideoFrame& frame, FILE* file) {
+  if (frame.IsZeroSize())
+    return -1;
   return PrintVideoFrame(*frame.video_frame_buffer(), file);
 }