Use a per-isolate cache for the date object JS bits

test/cctest/test-date.cc

 // 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 149 matching lines @@
     CheckDST(TimeFromYearMonthDay(date_cache, year, 5, 5));
   }
   CheckDST((august_20 + september_10) / 2);
   CheckDST(september_10);
   CheckDST(september_10 + 2 * 3600);
   CheckDST(september_10 + 2 * 3600 - 1000);
   CheckDST(august_20 + 2 * 3600);
   CheckDST(august_20 + 2 * 3600 - 1000);
   CheckDST(august_20);
 }
+
+
+TEST(DateCacheVersion) {
+  FLAG_allow_natives_syntax = true;
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::Isolate::Scope isolate_scope(isolate);
+  v8::HandleScope scope(isolate);
+  v8::Handle<v8::Context> context = v8::Context::New(isolate);
+  v8::Context::Scope context_scope(context);
+  v8::Handle<v8::Array> date_cache_version =
+      v8::Handle<v8::Array>::Cast(CompileRun("%DateCacheVersion()"));
+
+  CHECK_EQ(1, static_cast<int32_t>(date_cache_version->Length()));
+  CHECK(date_cache_version->Get(0)->IsNumber());
+  CHECK_EQ(0.0, date_cache_version->Get(0)->NumberValue());
+
+  v8::Date::DateTimeConfigurationChangeNotification(isolate);
+
+  CHECK_EQ(1, static_cast<int32_t>(date_cache_version->Length()));
+  CHECK(date_cache_version->Get(0)->IsNumber());
+  CHECK_EQ(1.0, date_cache_version->Get(0)->NumberValue());
+}