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

BUG=
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/23767009

Patch from Ross McIlroy <rmcilroy@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16607 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -817,6 +817,21 @@ class V8_EXPORT HandleScope {
 };
 
 
+/**
+ * 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 ---
 
 

src/globals.h

@@ -393,18 +393,6 @@ enum LanguageMode {
 };
 
 
-// A simple Maybe type, that can be passed by 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;
-};
-
-
 // The Strict Mode (ECMA-262 5th edition, 4.2.2).
 //
 // This flag is used in the backend to represent the language mode. So far