Break backwards traversal loop if we have looped around all packet in the PacketBuffer for H264 fra…

webrtc/modules/video_coding/video_packet_buffer_unittest.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 459 matching lines @@
 
 TEST_F(TestPacketBuffer, ContinuousSeqNumDoubleMarkerBit) {
   Insert(2, kKeyFrame, kNotFirst, kNotLast);
   Insert(1, kKeyFrame, kFirst, kLast);
   frames_from_callback_.clear();
   Insert(3, kKeyFrame, kNotFirst, kLast);
 
   EXPECT_EQ(0UL, frames_from_callback_.size());
 }
 
+TEST_F(TestPacketBuffer, OneH264FrameFillBuffer) {
+  VCMPacket packet;
+  packet.seqNum = 0;
+  packet.codec = kVideoCodecH264;
+  packet.dataPtr = nullptr;
+  packet.sizeBytes = 0;
+  packet.is_first_packet_in_frame = true;
+  packet.markerBit = false;
+  packet_buffer_->InsertPacket(&packet);
+
+  packet.is_first_packet_in_frame = false;
+  for (int i = 1; i < kStartSize - 1; ++i) {
+    packet.seqNum = i;
+    packet_buffer_->InsertPacket(&packet);
+  }
+
+  packet.seqNum = kStartSize - 1;
+  packet.markerBit = true;
+  packet_buffer_->InsertPacket(&packet);
+
+  EXPECT_EQ(1UL, frames_from_callback_.size());
+  CheckFrame(0);
+}
+
 }  // namespace video_coding
 }  // namespace webrtc