Bug 139986 [CommonNavigator] Convert catch(Error/Throwable) to SafeRunner
In several places the CN framework uses catch(Error/Throwable) to ensure that code does not bring the framework down. Change these to use SafeRunner.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonDragAdapter.java
public void dragStart(DragSourceEvent event) {
		if (Policy.DEBUG_DND) {
			System.out.println("CommonDragAdapter.dragStart (begin): " + event); 
		}
		try {
			
			DragSource dragSource = (DragSource) event.widget;
			if (Policy.DEBUG_DND) {
				System.out.println("CommonDragAdapter.dragStart source: " + dragSource); 
			}
			Control control = dragSource.getControl();
			if (control == control.getDisplay().getFocusControl()) {
				ISelection selection = provider.getSelection();
				assistantsToUse.clear();
				
				if (!selection.isEmpty()) {
					LocalSelectionTransfer.getTransfer().setSelection(selection);
					boolean doIt = false;
					INavigatorDnDService dndService = contentService.getDnDService();
					CommonDragAdapterAssistant[] assistants = dndService.getCommonDragAssistants();
					if (assistants.length == 0)
						doIt = true;
					for (int i = 0; i < assistants.length; i++) {
						if (Policy.DEBUG_DND) {
							System.out.println("CommonDragAdapter.dragStart assistant: " + assistants[i]); 
						}
						event.doit = true;
						assistants[i].dragStart(event, (IStructuredSelection) selection);
						doIt |= event.doit;
						if (event.doit) {