Move Maybe template into v8.h so it can be used by SetResourceConstraints

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 859 matching lines @@
 
   // Allow for the active closing of HandleScopes which allows to pass a handle
   // from the HandleScope being closed to the next top most HandleScope.
   bool is_closed_;
   internal::Object** RawClose(internal::Object** value);
 
   friend class ImplementationUtilities;
 };
 
 
+/**
+ * A simple Maybe type, representing an object which may or may not have a
+ * value.
+ */
+template<class T>
+struct Maybe {
+  Maybe() : has_value(false) {}
+  explicit Maybe(T t) : has_value(true), value(t) {}
+  Maybe(bool has, T t) : has_value(has), value(t) {}
+
+  bool has_value;
+  T value;
+};
+
+
 // --- Special objects ---
 
 
 /**
  * The superclass of values and API object templates.
  */
 class V8_EXPORT Data {
  private:
   Data();
 };
@@ skipping 5644 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_