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/extensions/NavigatorContentDescriptor.java
return icon;
	}
	/**
	 * @return Returns the suppressedExtensionId or null if none specified.
	 */
	public String getSuppressedExtensionId() {
		return suppressedExtensionId;
	}
	/**
	 * @return Returns the overridePolicy or null if this extension does not
	 *         override another extension.
	 */
	public OverridePolicy getOverridePolicy() {
		return overridePolicy;
	}
	/**
	 * @return Returns the contribution.
	 */
	public IPluginContribution getContribution() {
		return contribution;
	}
	/**
	 * The content provider could be an instance of
	 * {@link ICommonContentProvider}, but only {@link ITreeContentProvider} is
	 * required.
	 * 
	 * 
	 * @return An instance of the Content provider defined for this extension.
	 * @throws CoreException
	 *             if an instance of the executable extension could not be