html_viewer: Move webcrypto to a place where html_viewer can use it.

content/child/webcrypto/algorithm_registry.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_ALGORITHM_REGISTRY_H_
-#define CONTENT_CHILD_WEBCRYPTO_ALGORITHM_REGISTRY_H_
-
-#include "third_party/WebKit/public/platform/WebCrypto.h"
-
-namespace content {
-
-namespace webcrypto {
-
-class AlgorithmImplementation;
-class Status;
-
-// Retrieves the AlgorithmImplementation applicable for |id|.
-//
-// If there is no available implementation, then an error is returned, and
-// *impl is set to NULL.
-//
-// Otherwise Success is returned and *impl is set to a non-NULL value. The
-// AlgorithmImplementation pointer will remain valid until the program's
-// termination.
-Status GetAlgorithmImplementation(blink::WebCryptoAlgorithmId id,
-                                  const AlgorithmImplementation** impl);
-
-}  // namespace webcrypto
-
-}  // namespace content
-
-#endif  // CONTENT_CHILD_WEBCRYPTO_ALGORITHM_REGISTRY_H_