Non-interactive isearch-continue-forward and -backward, bound to S and R
in content_buffer_normal_keymap, wrap the search to the viewport instead
of the page when they are past the last match.  These commands should
cause isearch to wrap to the page, not the viewport.

This can be fixed by changing the isearch_continue_noninteractively function in modules/isearch.js to this:

function isearch_continue_noninteractively (window, direction) {
    var s = new isearch_session(window.minibuffer, direction);
    if (window.isearch_last_search) {
        s.find(window.isearch_last_search, direction, s.top.point);
        window.minibuffer.push_state(s);
        s.restore_state();
        isearch_continue (window, direction);
    }
    else
        throw "No previous isearch";
    isearch_done(window, true);
}

I'll gladly submit a patch or a pull request if you tell me where and how.

Thanks for a wonderful browsing experience :)