Bug 198239 Memory leak using script and also localized strings
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/script/ScriptHandler.java
* Unregister a variable from current JavaScript context.
	 * 
	 * @param sVarName
	 * @throws ChartException
	 */
	public final void unregisterVariable( String sVarName )
			throws ChartException
	{
		scope.delete( sVarName );
	}
	/**
	 * Finds the JavaScript funtion by given name.
	 * 
	 * @param sFunctionName
	 *            The name of the function to be searched for
	 * @return An instance of the function being searched for or null if it
	 *         isn't found
	 */
	private final Function getJavascriptFunction( String sFunctionName )
	{
		
		
		if ( javaScriptFunctionNamesCache == null
				|| javaScriptFunctionNamesCache.indexOf( sFunctionName ) < 0 )
		{
			return null;
		}
		Context.enter( );
		try
		{