Make WebMIDI use blink Promise.

Source/bindings/v8/DOMRequestState.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 26 matching lines @@
 class DOMRequestState {
 public:
     explicit DOMRequestState(ExecutionContext* executionContext)
         : m_isolate(toIsolate(executionContext))
         , m_executionContext(executionContext)
         , m_world(DOMWrapperWorld::current(m_isolate))
     {
         ASSERT(m_executionContext);
     }
 
+    DOMRequestState(ExecutionContext* executionContext, PassRefPtr<DOMWrapperWorld> world)
+        : m_executionContext(executionContext)
+        , m_world(world)
+        , m_isolate(toIsolate(executionContext))
+    {
+    }
+
+    DOMRequestState(ExecutionContext* executionContext, DOMWrapperWorld* world)
+        : m_executionContext(executionContext)
+        , m_world(world)
+        , m_isolate(toIsolate(executionContext))
+    {
+    }
+
     void clear()
     {
         m_executionContext = 0;
         m_world.clear();
     }
 
     class Scope {
     public:
         explicit Scope(DOMRequestState& state)
             : m_handleScope(state.isolate())
@@ skipping 19 matching lines @@
     bool isValid() const { return m_executionContext; }
 
 private:
     v8::Isolate* m_isolate;
     ExecutionContext* m_executionContext;
     RefPtr<DOMWrapperWorld> m_world;
 };
 
 }
 #endif