Conver FileAccessProvider to use CancelableTaskTracker

BUG=155883


Review URL: https://chromiumcodereview.appspot.com/11369201

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@167740 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed