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
Object imageMap = null;
				byte[] imageContent = new byte[0];
				Object image = output;
				if ( type == IReportItemPresentation.OUTPUT_AS_IMAGE_WITH_MAP )
				{
					
					Object[] imageWithMap = (Object[]) output;
					if ( imageWithMap.length > 0 )
					{
						image = imageWithMap[0];
					}
					if ( imageWithMap.length > 1 )
					{
						imageMap = imageWithMap[1];
					}
				}
				if ( image instanceof InputStream )
				{
					imageContent = readContent( (InputStream) image );
				}
				else if ( output instanceof byte[] )
				{
					imageContent = (byte[]) image;
				}
				else
				{
					assert false;
					logger.log( Level.WARNING,
							"unsupported image type:{0}", output );