Do not create download directory on startup, except on ChromeOS.
Do not create download directory on startup, except on ChromeOS.

BUG=56021
TEST=see bug

Review URL: http://codereview.chromium.org/3471009

git-svn-id: http://src.chromium.org/svn/trunk/src@60279 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 15d21cee0aa3422963a182a0726a17722528023c
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