Bug 189622 DesignElementHandle.getMethods( ) shouldn't return null value
The return type of DesignElementHandle.getMethods( ) is List; if the design element handle doesn't have script methods, then it return null value. The return value is empty list will be better.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/extension/PeerExtensibilityProvider.java
* <code>IReportItem</code>.
	 * 
	 * @return the extension element
	 */
	public IReportItem getExtensionElement( )
	{
		return reportItem;
	}
	/**
	 * Gets the script definition of this extended element.
	 * 
	 * @return the script definition
	 */
	public IPropertyDefinition getScriptPropertyDefinition( )
	{
		if ( reportItem != null )
			return reportItem.getScriptPropertyDefinition( );
		return null;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.extension.ExtensibilityProvider#hasLocalPropertyValues()
	 */
	public boolean hasLocalPropertyValues( )
	{
		if ( !extensionPropValues.isEmpty( )
				|| hasLocalPropertyValuesOnOwnModel( ) )
			return true;
		return false;