[Win32] Avoid broken UI when DPI change handler fails #2432

In case a DPI change handler fails with an exception, the complete
rescaling process may fail. As an example, it may happen that an image
set to an Item has already been disposed when a DPI change event occurs,
but the DPI change handler still tries to set that image on the item
again, leading to an exception because of the image being disposed.

This change ensures that an exception happening when processing a DPI
change handler does not result in a complete rescaling failure and
instead reports the listener error to the Display.

Contributes to
#2432

Author: HeikoKlare

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/DPIZoomChangeRegistry.java

@@ -53,7 +53,11 @@ public static void applyChange(Widget widget, int newZoom, float scalingFactor)
 			Class<? extends Widget> clazz = entry.getKey();
 			DPIZoomChangeHandler handler = entry.getValue();
 			if (clazz.isInstance(widget)) {
-				handler.handleDPIChange(widget, newZoom, scalingFactor);
+				try {
+					handler.handleDPIChange(widget, newZoom, scalingFactor);
+				} catch (RuntimeException ex) {
+					widget.getDisplay().getRuntimeExceptionHandler().accept(ex);
+				}
 			}
 		}
 		Event event = new Event();