Store JSGlobalProxy's identity hash directly on the proxy itself

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 5f82bd7f2e7ee184975588e4de3e6b7fcebbe325..d76d8ba9e3f00591e9be9121728854a776d84d89 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -2748,6 +2748,25 @@ THREADED_TEST(IdentityHash) {
 }
 
 
+THREADED_TEST(GlobalProxyIdentityHash) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope scope(isolate);
+  Handle<Object> global_proxy = env->Global();
+  int hash1 = global_proxy->GetIdentityHash();
+  // Hash should be retained after being detached.
+  env->DetachGlobal();
+  int hash2 = global_proxy->GetIdentityHash();
+  CHECK_EQ(hash1, hash2);
+  {
+    // Re-attach global proxy to a new context, hash should stay the same.
+    LocalContext env2(NULL, Handle<ObjectTemplate>(), global_proxy);
+    int hash3 = global_proxy->GetIdentityHash();
+    CHECK_EQ(hash1, hash3);
+  }
+}
+
+
 THREADED_TEST(SymbolProperties) {
   i::FLAG_harmony_symbols = true;