- some middle-mouse-button-related fixes

        These don't affect Safari since it maps the middle mouse button to the command key,
        but that might not always be the case for future versions.

        * WebView/WebHTMLView.mm:
        (-[WebHTMLView otherMouseDown:]): Pass through middle mouse down events to WebCore.
        (-[WebHTMLView otherMouseDragged:]): Ditto, for drag events.
        (-[WebHTMLView otherMouseUp:]): Ditto, for up events.

        * WebView/WebPolicyDelegate.h: Fixed inaccurate documentation of WebActionButtonKey.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@28061 268f45cc-cd09-0410-ab3c-d52691b4dbfc