RFR: 8201567: QuantumRenderer modifies buffer in use by JavaFX Application Thread

[Kevin Rushforth]

On Fri, 26 Jun 2020 03:47:55 GMT, John Neffenger <github.com+1413266+jgneff at openjdk.org> wrote:

> Fixes [JDK-8201567](https://bugs.openjdk.java.net/browse/JDK-8201567).

At first glance the fix looks fine (aside from the `assert` statements that need to be removed). It will also need to
be tested using the SW pipeline on all platforms.

modules/javafx.graphics/src/main/java/com/sun/glass/ui/Pixels.java line 194:

> 193:     public final Buffer getBuffer() {
> 194:         assert this.bytes != null || this.ints != null;
> 195:         return this.bytes != null ? this.bytes : this.ints;

We should not use `assert` statements in the JavaFX runtime. If this is a condition that needs to be checked, then use
an `if` test and throw an appropriate `RuntimeException` or an `InternalError`.

-------------

PR: https://git.openjdk.java.net/jfx/pull/255