Revert of Delete cryptstring.h and cryptstring.cc.

Revert of Delete cryptstring.h and cryptstring.cc. (patchset #1 id:1 of https://codereview.webrtc.org/2740633003/ )

Reason for revert:
It turns out cryptstring was used by Chrome. In the xmpp code recently moved there from webrtc.

So this code has to be moved too, it canät just be deleted.

Original issue's description:
> Delete cryptstring.h and cryptstring.cc.
> 
> They became unused with cl https://codereview.webrtc.org/2731673002/
> 
> BUG=webrtc:6424
> 
> Review-Url: https://codereview.webrtc.org/2740633003
> Cr-Commit-Position: refs/heads/master@{#17128}
> Committed: https://chromium.googlesource.com/external/webrtc/+/822638b48111800434d7d4be6fef2f27c4e6e451

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6424
Review-Url: https://codereview.webrtc.org/2742743002
Cr-Commit-Position: refs/heads/master@{#17130}
Committed: https://chromium.googlesource.com/external/webrtc/+/d6652076011363ab329d5cc4643619e4728303c7

[nisse-webrtc, 2017-03-09 08:35:51]

The CQ bit was checked by nisse@webrtc.org

[nisse-webrtc, 2017-03-09 08:35:51]

Created Revert of Delete cryptstring.h and cryptstring.cc.

[commit-bot: I haz the power, 2017-03-09 08:35:59]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-03-09 08:36:05]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1489048551332550, "parent_rev":
"873abbd6cedbb2fab9e0dbe596e869d3f84e9c08", "commit_rev":
"d6652076011363ab329d5cc4643619e4728303c7"}

[commit-bot: I haz the power, 2017-03-09 08:36:07]

Description was changed from

==========
Revert of Delete cryptstring.h and cryptstring.cc. (patchset #1 id:1 of
https://codereview.webrtc.org/2740633003/ )

Reason for revert:
It turns out cryptstring was used by Chrome. In the xmpp code recently moved
there from webrtc.

So this code has to be moved too, it canät just be deleted.

Original issue's description:
> Delete cryptstring.h and cryptstring.cc.
> 
> They became unused with cl https://codereview.webrtc.org/2731673002/
> 
> BUG=webrtc:6424
> 
> Review-Url: https://codereview.webrtc.org/2740633003
> Cr-Commit-Position: refs/heads/master@{#17128}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/822638b48111800434d7d4be6...

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6424
==========

to

==========
Revert of Delete cryptstring.h and cryptstring.cc. (patchset #1 id:1 of
https://codereview.webrtc.org/2740633003/ )

Reason for revert:
It turns out cryptstring was used by Chrome. In the xmpp code recently moved
there from webrtc.

So this code has to be moved too, it canät just be deleted.

Original issue's description:
> Delete cryptstring.h and cryptstring.cc.
> 
> They became unused with cl https://codereview.webrtc.org/2731673002/
> 
> BUG=webrtc:6424
> 
> Review-Url: https://codereview.webrtc.org/2740633003
> Cr-Commit-Position: refs/heads/master@{#17128}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/822638b48111800434d7d4be6...

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6424

Review-Url: https://codereview.webrtc.org/2742743002
Cr-Commit-Position: refs/heads/master@{#17130}
Committed:
https://chromium.googlesource.com/external/webrtc/+/d6652076011363ab329d5cc46...
==========

[commit-bot: I haz the power, 2017-03-09 08:36:08]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/d6652076011363ab329d5cc46...

[nisse-webrtc, 2017-03-10 08:27:30]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.webrtc.org/2745523004/ by nisse@webrtc.org.

The reason for reverting is: CryptString usage is now deleted in Chrome, see cl
https://codereview.chromium.org/2738973004/.