Bug 183733 Implement the IScriptOjectClassInfo to provide the class infromation to support the JS code assistant.
Engine should implement the IScriptObjectClassInfo interface to return the class information for script object.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/ScriptedDesignVisitor.java
*            the entry point to the DE report design IR
	 * @param executionContext -
	 *            the execution context to execute the onPrepare script
	 */
	ScriptedDesignVisitor( ReportDesignHandle handle,
			ExecutionContext executionContext )
	{
		super( );
		this.handle = handle;
		this.executionContext = executionContext;
	}
	private void handleOnPrepare( ReportItemHandle handle )
	{
		boolean hasJavaScript = ( handle.getOnPrepare( ) != null )
				&& ( handle.getOnPrepare( ).length( ) != 0 );
		boolean hasJavaCode = ( handle.getEventHandlerClass( ) != null )
				&& ( handle.getEventHandlerClass( ).length( ) != 0 );
		if ( !hasJavaScript && !hasJavaCode )
			return;
		executionContext.pushHandle( handle );
		try
		{
			if ( handle instanceof DataItemHandle )
			{
				DataItemScriptExecutor.handleOnPrepare(
						( DataItemHandle ) handle, executionContext );
			} else if ( handle instanceof GridHandle )
			{
				GridScriptExecutor.handleOnPrepare( ( GridHandle ) handle,
						executionContext );