Remove unnecessary RTPHeaderParser, following https://codereview.webrtc.org/2659563002/

webrtc/call/call.cc

 /*
  *  Copyright (c) 2013 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 189 matching lines @@
     ReceiveRtpConfig(const std::vector<RtpExtension>& extensions,
                      bool transport_cc)
         : extensions(extensions), transport_cc(transport_cc) {}
 
     // Registered RTP header extensions for each stream. Note that RTP header
     // extensions are negotiated per track ("m= line") in the SDP, but we have
     // no notion of tracks at the Call level. We therefore store the RTP header
     // extensions per SSRC instead, which leads to some storage overhead.
     RtpHeaderExtensionMap extensions;
     // Set if the RTCP feedback message needed for send side BWE was negotiated.
-    bool transport_cc;
+    bool transport_cc = false;

[nisse-webrtc, 2017/02/01 14:50:17]

Does style guide suggest always providing default values?

This field ought to always be initialized by the constructor. Use of the default
constructor is an error (but unfortunately it is required because std::map
assignment seems to use the default constructor + assignment operator. If you
know any way to delete the default constructor, that would be nice).

I intentionally left it uninitialized here, since that lets tools like valgrind
and msan detect any improper use of the uninitialized value. Adding a default
value here defeats those tools. 

[the sun, 2017/02/01 15:12:06]

I don't know. It's a habit that has saved me many times though.
That's a good argument, but relies on test coverage and infrastructure to hold.
By always initializing members we will get consistent behavior in the case where
the data type is used in the wrong way, thus making bugs easier to find.

IMO, the only place where it would be a good idea to not initialize members
would be in inner loops.

[nisse-webrtc, 2017/02/02 08:10:11]

Ok.

   };
   std::map<uint32_t, ReceiveRtpConfig> receive_rtp_config_
       GUARDED_BY(receive_crit_);
 
   std::unique_ptr<RWLockWrapper> send_crit_;
   // Audio and Video send streams are owned by the client that creates them.
   std::map<uint32_t, AudioSendStream*> audio_send_ssrcs_ GUARDED_BY(send_crit_);
   std::map<uint32_t, VideoSendStream*> video_send_ssrcs_ GUARDED_BY(send_crit_);
   std::set<VideoSendStream*> video_send_streams_ GUARDED_BY(send_crit_);
 
@@ skipping 1024 matching lines @@
   if (transport_cc != header.extension.hasTransportSequenceNumber) {
     LOG(LS_ERROR) << "Inconsistent configuration of send side BWE.";
     return;
   }
   congestion_controller_->OnReceivedPacket(packet.arrival_time_ms(),
                                            packet.payload_size(), header);
 }
 
 }  // namespace internal
 }  // namespace webrtc