Reland of Fix off-by-one bugs in PacketBuffer when the buffer is filled with a single frame.

webrtc/modules/video_coding/frame_object.cc

 /*
  *  Copyright (c) 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 75 matching lines @@
           frame_type_ = kVideoFrameKey;
           break;
         }
       }
     }
   } else {
     _frameType = first_packet->frameType;
     frame_type_ = first_packet->frameType;
   }
 
-  GetBitstream(_buffer);
+  bool bitstream_copied = GetBitstream(_buffer);
+  RTC_DCHECK(bitstream_copied);
   _encodedWidth = first_packet->width;
   _encodedHeight = first_packet->height;
 
   // FrameObject members
   timestamp = first_packet->timestamp;
 
   VCMPacket* last_packet = packet_buffer_->GetPacket(last_seq_num);
   RTC_CHECK(last_packet && last_packet->markerBit);
   // http://www.etsi.org/deliver/etsi_ts/126100_126199/126114/12.07.00_60/
   // ts_126114v120700p.pdf Section 7.4.5.
@@ skipping 81 matching lines @@
 rtc::Optional<RTPVideoTypeHeader> RtpFrameObject::GetCodecHeader() const {
   rtc::CritScope lock(&packet_buffer_->crit_);
   VCMPacket* packet = packet_buffer_->GetPacket(first_seq_num_);
   if (!packet)
     return rtc::Optional<RTPVideoTypeHeader>();
   return rtc::Optional<RTPVideoTypeHeader>(packet->video_header.codecHeader);
 }
 
 }  // namespace video_coding
 }  // namespace webrtc