Bug 190207 Integrate Aggregation builder with charts
Charts should be able to use aggregates in their databinding definition. The UI is missing the "Add Aggregation..." button in the chart databinding dialog.
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/ReportDataServiceProvider.java
URL[] urls = new URL[count];
		for ( int i = 0; i < count; i++ )
		{
			File file = new File( classPathArray[i] );
			try
			{
				urls[i] = file.toURL( );
			}
			catch ( MalformedURLException e )
			{
				urls[i] = null;
			}
		}
		return new URLClassLoader( urls, parent );
	}
	
	
	/* (non-Javadoc)
	 * @see org.eclipse.birt.chart.ui.swt.interfaces.IDataServiceProvider#getDataType(java.lang.String)
	 */
	public DataType getDataType( String expression )
	{
		if ( expression == null || expression.trim( ).length( ) == 0 )
		{
			return null;
		}
		Iterator iterator = itemHandle.columnBindingsIterator( );
		while ( iterator.hasNext( ) )
		{
			ComputedColumnHandle cc = (ComputedColumnHandle) iterator.next( );