<AWT Dev> [9] Review request for 8056151: Switching to GTK L&F on-the-fly leads to X Window System error RenderBadPicture

[Alexander Zvegintsev]

Hello,

please review the fix
http://cr.openjdk.java.net/~azvegint/jdk/9/8056151/00/
for the issue
https://bugs.openjdk.java.net/browse/JDK-8056151

There are several prerequisites for this crash:
enabled XRender pipeline, visible window with non-opaque background with 
L&F other than GTK.

Switching to GTK L&F leads to load_gtk() call. We crashing on 
gtk_init_check() call [0]. It invokes
some XLib functions internally. Hence, wrap it with awtLock is enough to 
fix the crash.

This fix also removes some unnecessary unboxing.

[0] 
http://hg.openjdk.java.net/jdk9/client/jdk/file/3850097b0fe9/src/java.desktop/unix/native/libawt_xawt/awt/gtk2_interface.c#l925

-- 
Thanks,

Alexander.