Disk cache: Don't attempt to create another external file after an unexpected failure.
Disk cache: Don't attempt to create another external file
after an unexpected failure.

BUG=64807
TEST=none


Review URL: http://codereview.chromium.org/6581016

git-svn-id: http://src.chromium.org/svn/trunk/src@76413 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 155c92b8f1d7ef610a00419022a363576ed8e0da
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser