Merge 13131 - Make the throbber throb sooner after you navigate. This fixes t...

Merge 13131 - Make the throbber throb sooner after you navigate. This fixes the new tab page,
which would not start throbbing until the load committed. I think this was always
broken, but switching the tab contents types covered it up.

Now I have a flag that goes along with the tab updating that indicates if it's
a load update or a full update. This is necessary to avoid updating the title
to the page's URL until it does actually commit.

BUG=9310
Review URL: http://codereview.chromium.org/60066
TBR=brettw@chromium.org

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=13567