Revert of Introduce an IsMutable method on VideoFrameBuffer.

webrtc/common_video/video_frame.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 47 matching lines @@
   RTC_DCHECK_GE(stride_u, half_width);
   RTC_DCHECK_GE(stride_v, half_width);
 
   // Creating empty frame - reset all values.
   timestamp_ = 0;
   ntp_time_ms_ = 0;
   render_time_ms_ = 0;
   rotation_ = kVideoRotation_0;
 
   // Check if it's safe to reuse allocation.
-  if (video_frame_buffer_ && video_frame_buffer_->IsMutable() &&
+  if (video_frame_buffer_ && video_frame_buffer_->HasOneRef() &&
       !video_frame_buffer_->native_handle() &&
       width == video_frame_buffer_->width() &&
       height == video_frame_buffer_->height() && stride_y == stride(kYPlane) &&
       stride_u == stride(kUPlane) && stride_v == stride(kVPlane)) {
     return;
   }
 
   // Need to allocate new buffer.
   video_frame_buffer_ = new rtc::RefCountedObject<I420Buffer>(
       width, height, stride_y, stride_u, stride_v);
@@ skipping 131 matching lines @@
     case kVideoCodecULPFEC:
     case kVideoCodecGeneric:
     case kVideoCodecUnknown:
       return 0;
   }
   RTC_NOTREACHED();
   return 0;
 }
 
 }  // namespace webrtc