[9] Review request for 8159892: Ubuntu 16.04: invalid rendering of FX app stage in case of scaling

[Jim Graham]

Bug: https://bugs.openjdk.java.net/browse/JDK-8159892
webrev: http://cr.openjdk.java.net/~flar/JDK-8159892/webrev.00/

There are a number of bugs filed on this, or very similar issues as well - all related to broken DPI scaling on GTK3.

It looks like there is a simple way of disabling automatic scaling for GTK3 so we can do our own (which has been working 
fairly well so far for GTK2 and is preferable to the integer-operation scaling we'd get automatically via the 
integer-dominated APIs of GDK/GTK).

Questions:

- Is this the best bug ID to use for this fix?  I used it as it was the first one that I looked at and it had screen 
shots of the problem that immediately pointed me to the underlying problem.  Other bugids are mentioned in the bug 
report as being "possible dups" and most of them should be a duplicate, but so far I've only tested the test case shown 
in the screen shots of 8159892...

- The new function is specifically in 3.10 of the GTK 3 libraries.  Should I add additional protections in case a system 
has an earlier 3.XX version of GTK3?

- Minor note - I discovered after publishing the webrev that the function is defined, declared, loaded and stubbed in 
inconsistent locations in the list of functions - not really an issue, but I'll try to normalize where it appears in all 
of the various function lists if I have to recut the webrev...

				...jim