bindings: Don't throw a TypeError when 'null' is passed to nullable callback function

third_party/WebKit/Source/core/testing/CallbackFunctionTest.h

 // Copyright 2016 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 CallbackFunctionTest_h
 #define CallbackFunctionTest_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Vector.h"
@@ skipping 15 matching lines @@
 
  public:
   DECLARE_TRACE();
 
   static CallbackFunctionTest* create() { return new CallbackFunctionTest(); }
 
   String testCallback(TestCallback*,
                       const String&,
                       const String&,
                       ExceptionState&);
+  String testNullableCallback(TestCallback*,
+                              const String&,
+                              const String&,
+                              ExceptionState&);
   void testInterfaceCallback(TestInterfaceCallback*,
                              HTMLDivElement*,
                              ExceptionState&);
   void testReceiverObjectCallback(TestReceiverObjectCallback*, ExceptionState&);
   Vector<String> testSequenceCallback(TestSequenceCallback*,
                                       const Vector<int>& numbers,
                                       ExceptionState&);
 };
 
 }  // namespace blink
 
 #endif  // CallbackFunctionTest_h