Make OverheadObserver::OnOverheadChanged count RTP headers only

webrtc/modules/rtp_rtcp/test/testAPI/test_api.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 112 matching lines @@
   EXPECT_EQ(test_sequence_number_, module_->SequenceNumber());
 
   module_->SetStartTimestamp(test_timestamp_);
   EXPECT_EQ(test_timestamp_, module_->StartTimestamp());
 
   EXPECT_FALSE(module_->Sending());
   EXPECT_EQ(0, module_->SetSendingStatus(true));
   EXPECT_TRUE(module_->Sending());
 }
 
-TEST_F(RtpRtcpAPITest, MTU) {
-  EXPECT_EQ(0, module_->SetMaxTransferUnit(1234));
-  EXPECT_EQ(1234 - 20 - 8, module_->MaxPayloadLength());
-
-  EXPECT_EQ(0, module_->SetTransportOverhead(true, true, 12));
-  EXPECT_EQ(1234 - 20 - 20 - 20 - 12, module_->MaxPayloadLength());
-
-  EXPECT_EQ(0, module_->SetTransportOverhead(false, false, 0));
-  EXPECT_EQ(1234 - 20 - 8, module_->MaxPayloadLength());
-
-  module_->SetTransportOverhead(28);
-  EXPECT_EQ(1234 - 28, module_->MaxPayloadLength());
-  module_->SetTransportOverhead(44);
-  EXPECT_EQ(1234 - 44, module_->MaxPayloadLength());
+TEST_F(RtpRtcpAPITest, PacketSize) {
+  module_->SetMaxRtpPacketSize(1234);
+  EXPECT_EQ(1234u, module_->MaxRtpPacketSize());
+  EXPECT_EQ(1234u - 12u /* Minimum RTP header */, module_->MaxPayloadSize());
 }
 
 TEST_F(RtpRtcpAPITest, SSRC) {
   module_->SetSSRC(test_ssrc_);
   EXPECT_EQ(test_ssrc_, module_->SSRC());
 }
 
 TEST_F(RtpRtcpAPITest, RTCP) {
   EXPECT_EQ(RtcpMode::kOff, module_->RTCP());
   module_->SetRTCPStatus(RtcpMode::kCompound);
@@ skipping 32 matching lines @@
   rtx_header.payloadType = kRtxPayloadType;
   EXPECT_TRUE(rtp_payload_registry_->IsRtx(rtx_header));
   rtx_header.ssrc = 0;
   EXPECT_FALSE(rtp_payload_registry_->IsRtx(rtx_header));
   rtx_header.ssrc = kRtxSsrc;
   rtx_header.payloadType = 0;
   EXPECT_TRUE(rtp_payload_registry_->IsRtx(rtx_header));
 }
 
 }  // namespace webrtc