Send session history offset and length parameters in the Navigate message to

      keep the renderer's notion of those values properly synchronized with the
NavigationController.

R=brettw
BUG=18062
TEST=see session_history_uitest.cc

Review URL: http://codereview.chromium.org/1090002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42022 0039d316-1c4b-4281-b951-d872f2087c98