Bug 199834 Enable access to IContent object in IReportItemPresentation layer
In IReportItemPresentation layer, the extended item may want to access properties from current IContent object, for example, bookmark, content style. So we need expose the content object in this layer.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/presentation/LocalizedContentVisitor.java
* handle the label.
	 * 
	 * @param label
	 *            label content
	 */
	public Object visitLabel( ILabelContent label, Object value )
	{
		handleOnRender( label );
		processLabel( label );
		return label;
	}
	/**
	 * process the label content
	 * 
	 * <li> localize the help text
	 * <li> localize the label content
	 * <li> handle it as it is an text
	 * 
	 * @param label
	 *            label object
	 */
	protected void processLabel( ILabelContent label )
	{
		String helpText = localize( label, label.getHelpKey( ), label.getHelpText( ) );
		label.setHelpText( helpText );
		
		if ( label.getText( ) == null )
		{
			String text = localize( label, label.getLabelKey( ), label.getLabelText( ) );
			label.setText( text );