Don't add to LoadStart and LoadEnd histograms if load event hasn't fired yet.
Don't add to LoadStart and LoadEnd histograms if load event hasn't fired yet.

BUG=64321
TEST=adhoc (visit http://www/~eisinger/redirect.html)

Review URL: http://codereview.chromium.org/5382006
Patch from James Simonsen <simonjam@chromium.org>.

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@69141 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser