Don't remember pages that returned a 404 status code in our history.
Don't remember pages that returned a 404 status code in our history.

BUG=18727
TEST=Make sure that we are properly recording all (and only) valid pages in our history.

Review URL: http://codereview.chromium.org/6475001

git-svn-id: http://src.chromium.org/svn/trunk/src@74382 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: b243c50a4c4f597e7ce3188902e1fcbab430730a
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