Bug 75711 AstProvider should not create AST if requested by SelectionListenerWithASTManager
3.1 M2 If SelectionListenerWithASTManager waits for an AST and the editor closes we should not create an AST for that one but return null instead.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/OverrideIndicatorLabelDecorator.java
* @see ILabelDecorator#decorateImage(Image, Object)
	 */
	public Image decorateImage(Image image, Object element) {
		int adornmentFlags= computeAdornmentFlags(element);
		if (adornmentFlags != 0) {
			ImageDescriptor baseImage= new ImageImageDescriptor(image);
			Rectangle bounds= image.getBounds();
			return getRegistry().get(new JavaElementImageDescriptor(baseImage, adornmentFlags, new Point(bounds.width, bounds.height)));
		}
		return image;
	}
	
	/**
	 * Note: This method is for internal use only. Clients should not call this method.
	 * @param element The element to decorate
	 * @return Resulting decorations (combination of JavaElementImageDescriptor.IMPLEMENTS
	 * and JavaElementImageDescriptor.OVERRIDES)
	 */
	public int computeAdornmentFlags(Object element) {
		if (element instanceof IMethod) {
			try {
				IMethod method= (IMethod) element;
				if (!method.getJavaProject().isOnClasspath(method)) {
					return 0;
				}
				int flags= method.getFlags();
				if (method.getDeclaringType().isClass() && !method.isConstructor() && !Flags.isPrivate(flags) && !Flags.isStatic(flags)) {
					int res= getOverrideIndicators(method);
					if (res != 0 && Flags.isSynchronized(flags)) {
						return res | JavaElementImageDescriptor.SYNCHRONIZED;