blink: Cleanup class forward declarations

third_party/WebKit/Source/modules/webmidi/MIDIInputMap.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 MIDIInputMap_h
 #define MIDIInputMap_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "modules/webmidi/MIDIInput.h"
 #include "modules/webmidi/MIDIPortMap.h"
 
 namespace blink {
 
-class ScriptState;
-
 class MIDIInputMap : public MIDIPortMap<MIDIInput>, public ScriptWrappable {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   explicit MIDIInputMap(const HeapVector<Member<MIDIInput>>&);
 };
 
 }  // namespace blink
 
 #endif