Revert 284192 due to a failing test.

content/child/webcrypto/structured_clone.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 CONTENT_CHILD_WEBCRYPTO_STRUCTURED_CLONE_H_
-#define CONTENT_CHILD_WEBCRYPTO_STRUCTURED_CLONE_H_
-
-#include "base/basictypes.h"
-#include "third_party/WebKit/public/platform/WebCrypto.h"
-
-namespace content {
-
-namespace webcrypto {
-
-class CryptoData;
-
-// Called on the target Blink thread.
-bool SerializeKeyForClone(const blink::WebCryptoKey& key,
-                          blink::WebVector<uint8>* key_data);
-
-// Called on the target Blink thread.
-bool DeserializeKeyForClone(const blink::WebCryptoKeyAlgorithm& algorithm,
-                            blink::WebCryptoKeyType type,
-                            bool extractable,
-                            blink::WebCryptoKeyUsageMask usage_mask,
-                            const CryptoData& key_data,
-                            blink::WebCryptoKey* key);
-
-}  // namespace webcrypto
-
-}  // namespace content
-
-#endif  // CONTENT_CHILD_WEBCRYPTO_STRUCTURED_CLONE_H_