Revert of Add mechanism to auto mount file systems in response to a URL request.

Revert of Add mechanism to auto mount file systems in response to a URL request. (https://codereview.chromium.org/195923002/)

Reason for revert:
Best guess that this broke
SyncFileSystemApiTest.WriteFileThenGetUsage
SyncFileSystemApiTest.GetFileStatuses
MediaGalleriesPlatformAppBrowserTest.MediaGalleriesCopyTo
on XP Tests(1).

Original issue's description:
> Add mechanism to auto mount file systems in response to a URL request.
> 
> This code adds a hook for when a file system URL request can not be cracked.
> It will allow external media galleries file systems to be lazily created.
> 
> BUG=160900
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=258064

TBR=kinuko@chromium.org,tzik@chromium.org,joi@chromium.org,sky@chromium.org,vandebo@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=160900
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=258261

[pneubeck (no reviews), 2014-03-20 10:00:08]

Created Revert of Add mechanism to auto mount file systems in response to a URL
request.

[commit-bot: I haz the power, 2014-03-20 10:00:22]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pneubeck@chromium.org/206253002/1

[commit-bot: I haz the power, 2014-03-20 10:01:24]

Change committed as 258261

[vandebo (ex-Chrome), 2014-03-20 16:38:13]

A revert of this CL has been created in
https://codereview.chromium.org/199903003/ by vandebo@chromium.org.

The reason for reverting is: This revert did not fix the breakage it was
suspected of..