Revert of Use DiscardableMemoryManager on Android.

Revert of Use DiscardableMemoryManager on Android. (https://codereview.chromium.org/195863005/)

Reason for revert:
Fails compile

http://goo.gl/qePAC4

Original issue's description:
> Use DiscardableMemoryManager on Android.
> 
> This allows userspace (DiscardableMemoryManager) to control eviction of
> unlocked DiscardableMemory instances to prevent the process from running out of
> address space in cases of heavy use of unlocked DiscardableMemory.
> 
> This also removes all the occurences of 'Android' from the ashmem allocator to
> allow it to be later used on ChromeOS.
> 
> BUG=327516, 334996
> R=reveman@chromium.org, willchan@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=267170

[Nikita (slow), 2014-04-30 11:08:31]

Created Revert of Use DiscardableMemoryManager on Android.

[commit-bot: I haz the power, 2014-04-30 11:08:47]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nkostylev@chromium.org/260673003/1

[commit-bot: I haz the power, 2014-04-30 11:08:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-30 11:08:48]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Nikita (slow), 2014-04-30 11:08:48]

The CQ bit was unchecked by nkostylev@chromium.org

[Nikita (slow), 2014-04-30 11:09:11]

Already reverted at https://codereview.chromium.org/264633002/

Closing.