Bug 180249 BPS39 - Centralized Chart Engine API
Centralized and clearer Engine API -Create one single entry point class ChartEngine in an api package so it's easy to find (with access to IGenerator, Serializer, Device Renderers) -Create a new IGenerator interface instead of exposing the Generator class.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/factory/Generator.java
helper.generateRuntimeSeries( expressionEvaluator, chart );
	}
	/**
	 * Since v2, it must be called before build( ), and should only be called
	 * once per design model.
	 * 
	 * @param model
	 *            Chart design model
	 * @param externalContext
	 *            External Context
	 * @param locale
	 *            Locale
	 * @return a runtime context used by build( )
	 * 
	 * @throws ChartException
	 * 
	 * @deprecated use
	 *             {@link #prepare(Chart, IExternalContext, IScriptClassLoader, ULocale)}
	 *             instead.
	 */
	public RunTimeContext prepare( Chart model,
			IExternalContext externalContext, IScriptClassLoader iscl,
			Locale locale ) throws ChartException
	{
		return prepare( model,
				externalContext,
				iscl,
				ULocale.forLocale( locale ) );
	}
	/**