hg: jdk/client: 8225118: Robot.createScreenCapture() returns black image on HiDPI linux with gtk3

[anton.tarasov at jetbrains.com]

Changeset: 37819ad0ac6f
Author:    ant
Date:      2019-06-06 15:46 +0300
URL:       http://hg.openjdk.java.net/jdk/client/rev/37819ad0ac6f

8225118: Robot.createScreenCapture() returns black image on HiDPI linux with gtk3
Reviewed-by: serb

! src/java.desktop/unix/native/libawt_xawt/awt/gtk3_interface.c
! src/java.desktop/unix/native/libawt_xawt/awt/gtk3_interface.h
! test/jdk/java/awt/Robot/HiDPIScreenCapture/HiDPIRobotScreenCaptureTest.java