Bug 162140 [Progress] Be more resilient to null args in StatusLine's progress monitor
bundles/org.eclipse.jface/src/org/eclipse/jface/action/StatusLine.java
/**
     * Returns true if the user does some UI action to cancel this operation.
     * (like hitting the Cancel button on the progress dialog).
     * The long running operation typically polls isCanceled().
     */
    public boolean isCanceled() {
        return fIsCanceled;
    }
    /**
     * Returns <code>true</true> if the ProgressIndication provides UI for canceling
     * a long running operation.
     * @return <code>true</true> if the ProgressIndication provides UI for canceling
     */
    public boolean isCancelEnabled() {
        return fCancelEnabled;
    }
    /**
     * Sets the cancel status. This method is usually called with the 
     * argument false if a client wants to abort a cancel action.
     */
    public void setCanceled(boolean b) {
        fIsCanceled = b;
        if (fCancelButton != null) {
			fCancelButton.setEnabled(!b);
		}
    }
    /**
     * Controls whether the ProgressIndication provides UI for canceling
     * a long running operation.
     * If the ProgressIndication is currently visible calling this method may have