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/extension/ReportItemPresentationBase.java
* @see org.eclipse.birt.report.engine.extension.IReportItemPresentation#getOutputType(java.lang.String,
	 *      java.lang.String)
	 */
	public int getOutputType( )
	{
		return OUTPUT_NONE;
	}
	public Object getOutputContent( )
	{
		return null;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.extension.IReportItemPresentation#getSize()
	 */
	public Size getSize( )
	{
		return null;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.extension.IReportItemPresentation#finish()
	 */
	public void finish( )
	{
	}
	/*
	 * (non-Javadoc)