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/internal/navigator/wizards/CommonWizardDescriptorManager.java
descriptors.add(descriptor);
			}
		}
		CommonWizardDescriptor[] enabledDescriptors = new CommonWizardDescriptor[descriptors.size()];
		return (CommonWizardDescriptor[]) descriptors.toArray(enabledDescriptors);  
	}
	/**
	 * @param aContentService
	 * @param descriptor
	 * @return True if the descriptor is visible to the given content service.
	 */
	private boolean isVisible(INavigatorContentService aContentService, CommonWizardDescriptor descriptor) {
		return !WorkbenchActivityHelper.filterItem(descriptor) && 
					(aContentService == null || 
							(descriptor.getId() == null || 
									( aContentService.isVisible(descriptor.getId()) && 
											aContentService.isActive(descriptor.getId())
									)
							)
					);
	}
  
	private class CommonWizardRegistry extends NavigatorContentRegistryReader {
 
		protected boolean readElement(IConfigurationElement anElement) {
			if (TAG_COMMON_WIZARD.equals(anElement.getName())) {
				try {
					addCommonWizardDescriptor(new CommonWizardDescriptor(
							anElement));
				} catch (WorkbenchException e) {