Remove frameID hack for history.

This isn't needed anymore since history is maintained by the embedder.

BUG=none
R=japhet@chromium.org

Review URL: https://codereview.chromium.org/296893009

git-svn-id: svn://svn.chromium.org/blink/trunk@174712 bbb929c8-8fbe-4397-9dbb-9b2b20218538