Bug 117601 [Undo] - update org.eclipse.core.commands.operations to use new equinox common utils
org.eclipse.core.commands.operations.DefaultOperationHistory - synchronizes its own listener list org.eclipse.core.commands.internal.util. - implements its own Assert. These should be updated to use the new support in org.eclipse.equinox.common
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/AbstractOperation.java
}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#addContext(org.eclipse.core.commands.operations.IUndoContext)
	 * 
	 * <p> Subclasses may override this method. </p>
	 */
	public void addContext(IUndoContext context) {
		if (!contexts.contains(context)) {
			contexts.add(context);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#canExecute()
	 *      <p> Default implementation. Subclasses may override this method.
	 *      </p>
	 * 
	 */
	public boolean canExecute() {
		return true;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#canRedo()
	 *      <p> Default implementation. Subclasses may override this method.
	 *      </p>