Don't clear newer packets from the video_coding::PacketBuffer when calling ClearTo;

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 285 matching lines @@
 TEST_F(TestPacketBuffer, ClearSinglePacket) {
   const uint16_t seq_num = Rand();
 
   for (int i = 0; i < kMaxSize; ++i)
     EXPECT_TRUE(Insert(seq_num + i, kDeltaFrame, kFirst, kLast));
 
   packet_buffer_->ClearTo(seq_num);
   EXPECT_TRUE(Insert(seq_num + kMaxSize, kDeltaFrame, kFirst, kLast));
 }
 
+TEST_F(TestPacketBuffer, ClearFullBuffer) {
+  for (int i = 0; i < kMaxSize; ++i)
+    EXPECT_TRUE(Insert(i, kDeltaFrame, kFirst, kLast));
+
+  packet_buffer_->ClearTo(kMaxSize - 1);
+
+  for (int i = kMaxSize; i < 2 * kMaxSize; ++i)
+    EXPECT_TRUE(Insert(i, kDeltaFrame, kFirst, kLast));
+}
+
+TEST_F(TestPacketBuffer, DontClearNewerPacket) {
+  EXPECT_TRUE(Insert(0, kKeyFrame, kFirst, kLast));
+  packet_buffer_->ClearTo(0);
+  EXPECT_TRUE(Insert(2 * kStartSize, kKeyFrame, kFirst, kLast));
+  EXPECT_TRUE(Insert(3 * kStartSize + 1, kKeyFrame, kFirst, kNotLast));
+  packet_buffer_->ClearTo(2 * kStartSize);
+  EXPECT_TRUE(Insert(3 * kStartSize + 2, kKeyFrame, kNotFirst, kLast));
+
+  ASSERT_EQ(3UL, frames_from_callback_.size());
+  CheckFrame(0);
+  CheckFrame(2 * kStartSize);
+  CheckFrame(3 * kStartSize + 1);
+}
+
 TEST_F(TestPacketBuffer, OneIncompleteFrame) {
   const uint16_t seq_num = Rand();
 
   EXPECT_TRUE(Insert(seq_num, kDeltaFrame, kFirst, kNotLast));
   EXPECT_TRUE(Insert(seq_num + 1, kDeltaFrame, kNotFirst, kLast));
   EXPECT_TRUE(Insert(seq_num - 1, kDeltaFrame, kNotFirst, kLast));
 
   ASSERT_EQ(1UL, frames_from_callback_.size());
   CheckFrame(seq_num);
 }
@@ skipping 263 matching lines @@
 
   ASSERT_EQ(1UL, frames_from_callback_.size());
   packet_buffer_->PaddingReceived(1);
   ASSERT_EQ(2UL, frames_from_callback_.size());
   CheckFrame(0);
   CheckFrame(2);
 }
 
 }  // namespace video_coding
 }  // namespace webrtc