Adding DateTimeFormat class to i18n API.

src/extensions/experimental/i18n-utils.h

Index: src/extensions/experimental/i18n-utils.h
===================================================================
--- src/extensions/experimental/i18n-utils.h	(revision 7878)
+++ src/extensions/experimental/i18n-utils.h	(working copy)
@@ -28,6 +28,14 @@
 #ifndef V8_EXTENSIONS_EXPERIMENTAL_I18N_UTILS_H_
 #define V8_EXTENSIONS_EXPERIMENTAL_I18N_UTILS_H_
 
+#include <v8.h>
+
+#include "unicode/uversion.h"
+
+namespace U_ICU_NAMESPACE {
+class UnicodeString;
+}
+
 namespace v8 {
 namespace internal {
 
@@ -40,6 +48,12 @@
   // TODO(cira): Find a way to use OS::SNPrintF instead.
   static void StrNCopy(char* dest, int length, const char* src);
 
+  // Extract a string setting named in |settings| and set it to |result|.
+  // Return true if it's specified. Otherwise, return false.
+  static bool ExtractStringSetting(const v8::Handle<v8::Object>& settings,
+                                   const char* setting,
+                                   icu::UnicodeString* result);
+
  private:
   I18NUtils() {}
 };