Revert 220123 "Remove simple_util::GetMTime from simple cache."
> Remove simple_util::GetMTime from simple cache.
>
> With base::PlatformFile::GetPlatformFileInfo now being high resolution, there's
> no need for this system specific cruft in the simple disk cache.
>
> R=clamy,pasko
> BUG=None
>
> Review URL: https://chromiumcodereview.appspot.com/
22571011
Reason: GetFileInfo is being used, and it is not high resolution right now.
TBR=gavinp@chromium.org
Review URL: https://codereview.chromium.org/
23597016
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221206 0039d316-1c4b-4281-b951-d872f2087c98