Rtp Packets in webrtc expected to be less that 1500, i.e. way less that 2^16 bytes for extensions block. This CL explicitly discards longer extension. Bug: chromium:809046 Change-Id: Ibed33b51bafc3fd4804ec135f66110c6d2796734 Reviewed-on: https://webrtc-review.googlesource.com/48061 Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Reviewed-by: Alex Loiko <aleloi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#21910}