Revert of Move MutableDataY{,U,V} methods to I420Buffer only.

webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter_unittest.cc

Index: webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter_unittest.cc
diff --git a/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter_unittest.cc b/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter_unittest.cc
index d13dbb165b7fac941abcfec17bb873beba9c65b0..47d2322d0b30c7e98136b8b6d530069d1f918d35 100644
--- a/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter_unittest.cc
+++ b/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter_unittest.cc
@@ -535,11 +535,17 @@
       .WillOnce(Return(WEBRTC_VIDEO_CODEC_FALLBACK_SOFTWARE));
 
   // Send a fake frame and assert the return is software fallback.
+  VideoFrame input_frame;
   int half_width = (kDefaultWidth + 1) / 2;
-  rtc::scoped_refptr<I420Buffer> input_buffer = I420Buffer::Create(
-      kDefaultWidth, kDefaultHeight, kDefaultWidth, half_width, half_width);
-  input_buffer->InitializeData();
-  VideoFrame input_frame(input_buffer, 0, 0, webrtc::kVideoRotation_0);
+  input_frame.CreateEmptyFrame(kDefaultWidth, kDefaultHeight, kDefaultWidth,
+                                half_width, half_width);
+  memset(input_frame.video_frame_buffer()->MutableDataY(), 0,
+         input_frame.allocated_size(kYPlane));
+  memset(input_frame.video_frame_buffer()->MutableDataU(), 0,
+         input_frame.allocated_size(kUPlane));
+  memset(input_frame.video_frame_buffer()->MutableDataV(), 0,
+         input_frame.allocated_size(kVPlane));
+
   std::vector<FrameType> frame_types(3, kVideoFrameKey);
   EXPECT_EQ(WEBRTC_VIDEO_CODEC_FALLBACK_SOFTWARE,
             adapter_->Encode(input_frame, nullptr, &frame_types));