Bug 195607 NPE is thrown when calling DimensionHandle:: getAbsoluteValue()
If a DimensionHandle did not set DimensionValue, NPE will thrown when calling DimensionHandle:: getAbsoluteValue().
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/FontSizeValueHandler.java
else if ( DimensionUtil.isRelativeFontSize( fontSizeConstant ) )
		{
			return getAbsoluteFontSizeValue( );
		}
		return null;
	}
	/**
	 * Tries to get an absolute font size constant. This method works only when
	 * the value is relative font size constant, otherwise, return null.
	 * 
	 * @return the absolute font size dimension value if possible
	 */
	private DimensionValue getAbsoluteFontSizeValue( )
	{
		Stack stack = new Stack( );
		boolean absoluteConstantFound = false;
		
		DesignElementHandle e = dimensionHandle.getElementHandle( );
		while ( e != null )
		{
			DimensionHandle fontSizeHandle = e
					.getDimensionProperty( IStyleModel.FONT_SIZE_PROP );
			if ( fontSizeHandle == null )
				break;
			Object value = fontSizeHandle.getValue( );
			if ( value instanceof DimensionValue )
				return (DimensionValue) value;
			String fontSizeConstant = (String) value;
			stack.push( fontSizeConstant );
			if ( DimensionUtil.isAbsoluteFontSize( fontSizeConstant ) )