Pulling in the remaining security patches from Chrome 57 and 58

Changes:
e7de22b [Backport] Clear the FrameBuffer in case of a backward jump in
 the picture id.
eccf7e6 [Backport] Don't update the jitter estimate with frames containing
 retransmitted packets.
0917c40 [Backport] Fix for CVE-2017-5068 (1/2)
9ae3b1f [Backport] Fix for CVE-2017-5068 (2/2)
67b158e [Backport] Fix of CVE-2017-5061 and CVE-2017-5067
b428c84 [Backport] Fix for CVE-2017-5052
f4df648 [Backport] Fix for CVE-2017-5053
ad6bdc3 [Backport] Fix for CVE-2017-5054

Change-Id: Ib853362fc17d64117937cfa59e2a7db8b4fd0c16
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>