code: public static Condition newRefererCondition(StringComparisonType comparisonType, String value) {
          return new StringCondition(comparisonType, REFERER_CONDITION_KEY, value);
      }
docs: Constructs a new access control policy condition that tests the incoming
  request's referer field against the specified value, using the specified
  comparison type.
  
  @param comparisonType
  The type of string comparison to perform when testing an
  incoming request's referer field with the specified value.
  @param value
  The value against which to compare the incoming request's
  referer field.
  
  @return A new access control policy condition that tests an incoming
  request's referer field.