Adds the listener to the collection of listeners who will be
notified when the current location has changed or is about to change.
<p>
This notification typically occurs when the application navigates
to a new location with {@link #setUrl(String)} or when the user
activates a hyperlink.
</p>
@param listener the listener which should be notified
@exception IllegalArgumentException <ul>
<li>ERROR_NULL_ARGUMENT - if the listener is null</li>
</ul>
@exception SWTException <ul>
<li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
<li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
</ul>
Adds the listener to the collection of listeners who will be notified when the current location has changed or is about to change. <p> This notification typically occurs when the application navigates to a new location with {@link #setUrl(String)} or when the user activates a hyperlink. </p>
@param listener the listener which should be notified
@exception IllegalArgumentException <ul> <li>ERROR_NULL_ARGUMENT - if the listener is null</li> </ul>
@exception SWTException <ul> <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li> <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li> </ul>
@since 3.0