Remove the Promises old implementation.

Source/bindings/v8/ScriptPromiseResolver.h

 /*
  * Copyright (C) 2013 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:
  *
  *     * 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
@@ skipping 135 matching lines @@
     template<typename T>
     v8::Handle<v8::Value> toV8Value(const T& value)
     {
         return ToV8Value<ScriptPromiseResolver, ScriptState*>::toV8Value(value, m_scriptState.get(), m_scriptState->isolate());
     }
 
     explicit ScriptPromiseResolver(ScriptState*);
 
     // FIXME: Remove this once ScriptValue::scriptState() becomes available.
     RefPtr<ScriptState> m_scriptState;
-    // Used when scriptPromiseOnV8Promise is disabled.
-    ScriptPromise m_promise;
-    // Used when scriptPromiseOnV8Promise is enabled.
     ScriptValue m_resolver;
 };
 
 } // namespace WebCore
 
 
 #endif // ScriptPromiseResolver_h