Delete IsZeroSize method.

webrtc/modules/video_processing/frame_preprocessor.cc

 /*
  *  Copyright (c) 2012 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 67 matching lines @@
 void VPMFramePreprocessor::EnableDenoising(bool enable) {
   if (enable) {
     denoiser_.reset(new VideoDenoiser(true));
   } else {
     denoiser_.reset();
   }
 }
 
 const VideoFrame* VPMFramePreprocessor::PreprocessFrame(
     const VideoFrame& frame) {
-  if (frame.IsZeroSize()) {
-    return nullptr;
-  }
 
   vd_->UpdateIncomingframe_rate();
   if (vd_->DropFrame()) {
     return nullptr;
   }
 
   const VideoFrame* current_frame = &frame;
   if (denoiser_) {
     rtc::scoped_refptr<I420Buffer>* denoised_buffer = &denoised_buffer_[0];
     rtc::scoped_refptr<I420Buffer>* denoised_buffer_prev = &denoised_buffer_[1];
@@ skipping 21 matching lines @@
       return nullptr;
     }
     current_frame = &resampled_frame_;
   }
 
   ++frame_cnt_;
   return current_frame;
 }
 
 }  // namespace webrtc