Stop using SHFileOperation from the disk cache code.
Stop using SHFileOperation from the disk cache code.

Using SHFileOperation to delete old cache files has the disadvantage that once in a while
somebody decides to perform COM operations assuming STA, and that doesn't work with the
worker pool.

BUG=1314744


git-svn-id: http://src.chromium.org/svn/trunk/src@590 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: cea808cd6242147c73d37c6acb9ee2ba0233203e
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