Clean up forward declarations in Source/modules

Source/modules/crypto/WorkerGlobalScopeCrypto.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 20 matching lines @@
 #ifndef WorkerGlobalScopeCrypto_h
 #define WorkerGlobalScopeCrypto_h
 
 #include "core/workers/WorkerGlobalScope.h"
 #include "platform/Supplementable.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class Crypto;
-class ExecutionContext;
 class WorkerGlobalScope;
 
 class WorkerGlobalScopeCrypto final : public NoBaseWillBeGarbageCollected<WorkerGlobalScopeCrypto>, public WillBeHeapSupplement<WorkerGlobalScope> {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(WorkerGlobalScopeCrypto);
 public:
     static WorkerGlobalScopeCrypto& from(WillBeHeapSupplementable<WorkerGlobalScope>&);
     static Crypto* crypto(WillBeHeapSupplementable<WorkerGlobalScope>&);
     Crypto* crypto() const;
 
     virtual void trace(Visitor*);
 
 private:
     WorkerGlobalScopeCrypto();
     static const char* supplementName();
 
     mutable PersistentWillBeMember<Crypto> m_crypto;
 };
 
 } // namespace blink
 
 #endif // WorkerGlobalScopeCrypto_h