Remove now unused code in RtpHeaderExtensionMap

webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
index bb41b83aaa6813ad8b67f115623fd23662dd8557..a4a2b150b4416c451bbaedf519581d2de43d1226 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
@@ -247,13 +247,8 @@ bool RTPSenderVideo::SendVideo(RtpVideoCodecTypes video_type,
   // (e.g. a P-Frame) only if the current value is different from the previous
   // value sent.
   // Here we are adding it to every packet of every frame at this point.
-  if (video_header && video_header->rotation != kVideoRotation_0) {
-    // TODO(danilchap): Remove next call together with concept
-    // of inactive extension. Now it helps to calulate total maximum size
-    // or rtp header extensions that is used in FECPacketOverhead() function.
-    rtp_sender_->ActivateCVORtpHeaderExtension();
+  if (video_header && video_header->rotation != kVideoRotation_0)

[sprang_webrtc, 2016/10/24 13:48:10]

Just to be clear, how exactly is this rotation extension supposed to work...
The "rotation != kVideoRotation_0" makes me worried we can get into a situation,
where we toggle to 90 rotation and then back to 0, but 0 won't be sent so we're
stuck a 90? Or do we always interpret lack of rotation extension as implicit 0
rotation?

[danilchap, 2016/10/24 14:27:25]

No rotation extension means it is 0.
Before my refactorings this extension was also skipped when rotation was 0, even
if previous was 90:
bool video_rotation_active = false;
if (video_header && video_header->rotation != kVideoRotation_0) {
  video_rotation_active = rtp_sender_->ActivateCVORtpHeaderExtension();
}

But before, even if extension was skipped, place for it was reserved as soon as
there was non-zero rotation at least once. Now the space is used only when
extension is actually set.
Before place in fec was reserved only after non-zero value was observed. Now
[with this CL] it is always reserved. (sure only if it is registered and fec is
enabled). 

[sprang_webrtc, 2016/10/25 07:47:00]

Acknowledged.

I interpreted the previous "rtp_sender_->ActivateCVORtpHeaderExtension()" call
to be sticky, so that the extension was first introduced when rotation != 0, but
was then kept for the rest of the call even when rotation returned to 0.

I'll trust you though. :)

     rtp_header->SetExtension<VideoOrientation>(video_header->rotation);
-  }
 
   size_t packet_capacity = rtp_sender_->MaxPayloadLength() -
                            FecPacketOverhead() -