Revert of media: Implement MediaDrmStorageImpl with tests (patchset #4 id:60001 of https://codereview.chromium.org/2791903004/ )

Reason for revert:
This CL causes MediaDrmStorageImplTest failing on chromium.linux/Android Tests:
https://uberchromegw.corp.google.com/i/chromium.linux/builders/Android%20Tests/builds/40330

BUG=709601

Original issue's description:
> media: Implement MediaDrmStorageImpl with tests
>
> Implement MediaDrmStorageImpl using PrefService.
>
> TBR=sdefresne@chromium.org
> BUG=493521
> TEST=New unit tests added.
>
> Review-Url: https://codereview.chromium.org/2791903004
> Cr-Commit-Position: refs/heads/master@{#462929}
> Committed: https://chromium.googlesource.com/chromium/src/+/d0b7b3b7e9f7d4e4c1f8276c5b416eaa05ac9bb0

TBR=yucliu@chromium.org,sdefresne@chromium.org,xhwang@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=493521

Review-Url: https://codereview.chromium.org/2808563002
Cr-Commit-Position: refs/heads/master@{#462988}
6 files changed