Reason for revert:
Breaks Chromium FYI bots.
tommi, please let me land this (I forgot to run them).
Original issue's description:
> Remove webrtc/libjingle/{xmllite,xmpp} as it's dead code.
>
> These sources have now been imported into Chromium's
> src/third_party/libjingle_xmpp.
>
> BUG=webrtc:5539
> NOTRY=True
>
> Review-Url: https://codereview.webrtc.org/2617443003
> Cr-Commit-Position: refs/heads/master@{#15910}
> Committed: 1670b1fe6b
TBR=tommi@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5539
Review-Url: https://codereview.webrtc.org/2618633003
Cr-Commit-Position: refs/heads/master@{#15911}