Revert of Delete VideoFrame default constructor, and IsZeroSize method.

webrtc/media/base/videobroadcaster_unittest.cc

 /*
  *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 19 matching lines @@
   EXPECT_FALSE(broadcaster.frame_wanted());
 }
 
 TEST(VideoBroadcasterTest, OnFrame) {
   VideoBroadcaster broadcaster;
 
   FakeVideoRenderer sink1;
   FakeVideoRenderer sink2;
   broadcaster.AddOrUpdateSink(&sink1, rtc::VideoSinkWants());
   broadcaster.AddOrUpdateSink(&sink2, rtc::VideoSinkWants());
-  static int kWidth = 100;
-  static int kHeight = 50;
 
-  rtc::scoped_refptr<webrtc::I420Buffer> buffer(
-      webrtc::I420Buffer::Create(kWidth, kHeight));
-  // Initialize, to avoid warnings on use of initialized values.
-  buffer->SetToBlack();
-
-  webrtc::VideoFrame frame(buffer, webrtc::kVideoRotation_0, 0);
+  webrtc::VideoFrame frame;
 
   broadcaster.OnFrame(frame);
   EXPECT_EQ(1, sink1.num_rendered_frames());
   EXPECT_EQ(1, sink2.num_rendered_frames());
 
   broadcaster.RemoveSink(&sink1);
   broadcaster.OnFrame(frame);
   EXPECT_EQ(1, sink1.num_rendered_frames());
   EXPECT_EQ(2, sink2.num_rendered_frames());
 
@@ skipping 101 matching lines @@
   broadcaster.AddOrUpdateSink(&sink2, wants2);
 
   webrtc::VideoFrame frame2(buffer, webrtc::kVideoRotation_0,
                             30 /* timestamp_us */);
   broadcaster.OnFrame(frame2);
   EXPECT_FALSE(sink1.black_frame());
   EXPECT_EQ(30, sink1.timestamp_us());
   EXPECT_TRUE(sink2.black_frame());
   EXPECT_EQ(30, sink2.timestamp_us());
 }