Revert of Delete VideoFrame default constructor, and IsZeroSize method.

webrtc/modules/video_coding/codecs/test/videoprocessor.h

Index: webrtc/modules/video_coding/codecs/test/videoprocessor.h
diff --git a/webrtc/modules/video_coding/codecs/test/videoprocessor.h b/webrtc/modules/video_coding/codecs/test/videoprocessor.h
index f87ccc5f2359565e9ce427bb8fd428437975267a..3142946509760a8a852fc5567565e1a6c504d26e 100644
--- a/webrtc/modules/video_coding/codecs/test/videoprocessor.h
+++ b/webrtc/modules/video_coding/codecs/test/videoprocessor.h
@@ -204,6 +204,7 @@
   // Keep track of the last successful frame, since we need to write that
   // when decoding fails:
   uint8_t* last_successful_frame_buffer_;
+  webrtc::VideoFrame source_frame_;
   // To keep track of if we have excluded the first key frame from packet loss:
   bool first_key_frame_has_been_excluded_;
   // To tell the decoder previous frame have been dropped due to packet loss: