Revert of Combine 'pssh' parsing routines.

Revert of Combine 'pssh' parsing routines. (patchset #7 id:120001 of https://codereview.chromium.org/1149023002/)

Reason for revert:
Broke Google Chrome Mac build: https://build.chromium.org/p/chromium.chrome/builders/Google%20Chrome%20Mac/builds/1748/steps/compile/logs/stdio

Original issue's description:
> Combine CENC 'pssh' box parsing routines.
>
> Also update the routines to ignore 'pssh' boxes with version 2 or
> later.
>
> BUG=460359, 460360
> TEST=new unittests pass
>
> Committed: https://crrev.com/b666d7874efac44b359a95329f0cb890e97671df
> Cr-Commit-Position: refs/heads/master@{#333556}

TBR=sandersd@chromium.org,ddorwin@chromium.org,xhwang@chromium.org,jrummell@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=460359, 460360
Committed: https://crrev.com/aaa96a77ea169e968e73a7d613deae52bfa369c5
Cr-Commit-Position: refs/heads/master@{#333568}

[Rune Fevang, 2015-06-09 20:43:20]

Created Revert of Combine 'pssh' parsing routines.

[commit-bot: I haz the power, 2015-06-09 20:44:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1170923005/1

[commit-bot: I haz the power, 2015-06-09 20:46:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-09 20:47:40]

Patchset 1 (id:??) landed as
https://crrev.com/aaa96a77ea169e968e73a7d613deae52bfa369c5
Cr-Commit-Position: refs/heads/master@{#333568}

[Nico, 2015-06-09 21:15:08]

thakis@chromium.org changed reviewers:
+ thakis@chromium.org

[Nico, 2015-06-09 21:15:08]

broke official windows builds too:
http://build.chromium.org/p/chromium.fyi/builders/CrWinClang/builds/1301/step...