This commit makes the UpdateInterface class immutable. The Config -> UpdateInterface initialization is moved to the UpdateInterface constructor. Default values for the fields are moved to the constructor as well. Instances of String[] are changed to List<String> and made immutable. Instances of java.awt.Rectangle (which is mutable) are replaced with a new immutable com.threerings.getdown.util.Rectangle class.
Although java.awt.Color is (sort of) immutable, it was also removed and replaced with a new immutable com.threerings.getdown.util.Color class, since it was the last dependency from the getdown core module to anything in the java.awt package, which means that when we migrate to Java 9+ the core module should no longer require a dependency on the java.desktop module.
The assertions and expected values in ColorTest have been verified against the corresponding java.awt.Color values.
(Triggered by internal security audit and Fortify analysis.)
Daniel Gredler
1f2c736564