/**
  * Checks validity of a RuleContext to produce an AndroidData.
  *
  * @throws RuleErrorException if the RuleContext is invalid. Accumulated errors will be available
  *     via {@code ruleContext}
  */
 public static void validateRuleContext(RuleContext ruleContext) throws RuleErrorException {
   validateAssetsAndAssetsDir(ruleContext);
   validateNoResourcesAttribute(ruleContext);
   validateNoAndroidResourcesInSources(ruleContext);
   validateManifest(ruleContext);
 }