[FileAPI] Ignore requests after QuotaReservation::OnClientCrash call.

When a client crash detected, the associated QuotaReservation object reclaims its reserved quota.
And then, in-flight operations should be ignored.

Review URL: https://codereview.chromium.org/139833006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245481 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245481