Convert plugin and GPU process to brokered handle duplication.

BUG=119250
Review URL: https://chromiumcodereview.appspot.com/9958034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@132303 0039d316-1c4b-4281-b951-d872f2087c98
  ~MessageFilter() {
    for (ModalDialogEventMap::iterator i = modal_dialog_event_map_.begin();
        i != modal_dialog_event_map_.end(); ++i) {
      delete i->second.event;
    }
  }

  ~MessageFilter() {
    for (ModalDialogEventMap::iterator i = modal_dialog_event_map_.begin();
        i != modal_dialog_event_map_.end(); ++i) {
      delete i->second.event;
    }
  }
