[OpenJDK 2D-Dev] RFR: 8245159: Font.getStringBounds() throws IAE for empty string if the Font has layout attributes.

[Philip Race]

bug : https://bugs.openjdk.java.net/browse/JDK-8245159
webrev: http://cr.openjdk.java.net/~prr/8245159/

TextLayout does not like being constructed with an empty string, so
when we accept a string from the application and  use it in
creating a TextLayout we need to be check.
I looked around for other cases that may be missing a check but did not 
spot any.

-phil.