gc plugin: remove ScriptWrappable destructor special case.

tools/clang/blink_gc_plugin/tests/class_requires_finalization_mixin.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 CLASS_REQUIRES_FINALIZATION_MIXIN_H_
 #define CLASS_REQUIRES_FINALIZATION_MIXIN_H_
 
 #include "heap/stubs.h"
 
 namespace blink {
@@ skipping 30 matching lines @@
                      public MixinFinalizable {
     USING_GARBAGE_COLLECTED_MIXIN(HasFinalizer);
 public:
     virtual void trace(Visitor*) override;
 private:
     Member<OnHeap> m_obj;
 };
 
 class NeedsNoFinalization
     : public GarbageCollected<NeedsNoFinalization>
-    , public MixinNotFinalizable
-    , public ScriptWrappable {
+    , public MixinNotFinalizable {
     USING_GARBAGE_COLLECTED_MIXIN(NeedsNoFinalization);
 public:
     virtual void trace(Visitor*) override;
 private:
     Member<OnHeap> m_obj;
 };
 
 }
 
 #endif