DevTools: do not crash on rapid refresh while on a Dev Tools Client window.
DevTools: do not crash on rapid refresh while on a Dev Tools Client window.

BUG=13494

Review URL: http://codereview.chromium.org/118494

git-svn-id: http://src.chromium.org/svn/trunk/src@18049 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 03fe8da6f336bdb1bb18ae75f2abfd1b6f45af01
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