Bug 210496 Add hasStyle property in reportItemModel extension point
When chart gets reportItem's properties by extending ReportItem, style properties are null. Hence, model needs to add hasStyle property in reportItemModel extension point
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/ElementDefn.java
* @throws MetaDataException
	 *             if build of any slot failed.
	 */
	protected void buildSlots( ) throws MetaDataException
	{
		if ( slots != null && slots.size( ) == 0 )
			slots = null;
		if ( slots == null )
			return;
		for ( int i = 0; i < slots.size( ); i++ )
		{
			SlotDefn slot = (SlotDefn) slots.get( i );
			slot.setSlotID( i );
			slot.build( );
		}
	}
	/**
	 * Returns a list of the localized property group names defined by this
	 * element and its parents.
	 * <p>
	 * The UI uses property groups to organize properties within the generic
	 * property sheet.
	 * 
	 * @return The list of group names. If there is no groups defined on the
	 *         element, the list will has no content.
	 */
	public List getGroupNames( )
	{
		
		ArrayList groupNames = new ArrayList( );