Introduce v8::MicrotasksScope.

test/cctest/test-microtask-delivery.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 87 matching lines @@
   CHECK_EQ(6,
            CompileRun("ordering[5]")->Int32Value(context.local()).FromJust());
 }
 
 
 TEST(MicrotaskPerIsolateState) {
   i::FLAG_harmony_object_observe = true;
   HarmonyIsolate isolate;
   v8::HandleScope scope(isolate.GetIsolate());
   LocalContext context1(isolate.GetIsolate());
-  isolate.GetIsolate()->SetAutorunMicrotasks(false);
+  isolate.GetIsolate()->SetMicrotasksPolicy(v8::MicrotasksPolicy::kExplicit);
   CompileRun(
       "var obj = { calls: 0 };");
   v8::Local<v8::Value> obj = CompileRun("obj");
   {
     LocalContext context2(isolate.GetIsolate());
     context2->Global()
         ->Set(context2.local(),
               v8::String::NewFromUtf8(isolate.GetIsolate(), "obj",
                                       v8::NewStringType::kNormal)
                   .ToLocalChecked(),
@@ skipping 33 matching lines @@
               v8::String::NewFromUtf8(isolate.GetIsolate(), "obj",
                                       v8::NewStringType::kNormal)
                   .ToLocalChecked(),
               obj)
         .FromJust();
     isolate.GetIsolate()->RunMicrotasks();
     CHECK_EQ(2,
              CompileRun("obj.calls")->Int32Value(context4.local()).FromJust());
   }
 }