Do not try to swap chrome.exe if machine is shutting down.
Do not try to swap chrome.exe if machine is shutting down.

BUG=18063
TEST=Installer an update while Chrome is running. Log out of machine without closing Chrome first and make sure sure Chrome gets updated cleanly whenever it is launched next.

Review URL: http://codereview.chromium.org/553079

git-svn-id: http://src.chromium.org/svn/trunk/src@37202 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: e83651cee5fa2c5f181a245329f0fa42f8bfb6f5
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