Bug 86135 Make use of new IResource#revertModificationStamp(long) API
org.eclipse.ltk.core.refactoring/src/org/eclipse/ltk/internal/core/refactoring/ContentStamps.java
private static class ContentStampImpl extends ContentStamp {
		
		public static final int NULL_VALUE= -1;
		
		private int fValue;
		
		private ContentStampImpl(int value) {
			fValue= value;
		}
		public boolean isNullStamp() {
			return fValue == NULL_VALUE;
		}
		public boolean equals(Object obj) {
			if (!(obj instanceof ContentStampImpl))
				return false;
			return ((ContentStampImpl)obj).fValue == fValue;
		}
		public int hashCode() {
			return fValue;
		}
		public String toString() {
			if (fValue == NULL_VALUE)
				return "Null Stamp";