Blink-in-JS: Implement internal APIs exposed only to private scripts

Source/core/testing/PrivateScriptTest.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PrivateScriptTest_h
 #define PrivateScriptTest_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 #include "wtf/RefCounted.h"
+#include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class LocalFrame;
 
 class PrivateScriptTest : public GarbageCollectedFinalized<PrivateScriptTest>, public ScriptWrappable {
 public:
     static PrivateScriptTest* create(LocalFrame* frame)
     {
         return new PrivateScriptTest(frame);
     }
 
+    int addIntegerImplementedInCPPForPrivateScriptOnly(int value1, int value2);
+    String stringAttributeImplementedInCPPForPrivateScriptOnly();
+    void setStringAttributeImplementedInCPPForPrivateScriptOnly(String);
+
     void trace(Visitor*) { }
 
 private:
-    PrivateScriptTest(LocalFrame*);
+    explicit PrivateScriptTest(LocalFrame*);
+
+    String m_stringAttributeImplementedInCPPForPrivateSriptOnly;
 };
 
 } // namespace blink
 
 #endif