Remove use of WebCrypto digestSynchronous in Blink.

Source/platform/Crypto.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.
 
 // TODO(jww) The original Blink-style header guard for this file conflicts with
 // the header guard in Source/modules/crypto/Crypto.h, so this is a
 // Chromium-style header guard instead. There is now a bug
 // (https://crbug.com/360121) to track a proposal to change all header guards
 // to a similar style. Thus, whenever that is resolved, this header guard
 // should be changed to whatever style is agreed upon.
@@ skipping 13 matching lines @@
 typedef Vector<uint8_t, kMaxDigestSize> DigestValue;
 
 const size_t sha1HashSize = 20;
 enum HashAlgorithm {
     HashAlgorithmSha1,
     HashAlgorithmSha256,
     HashAlgorithmSha384,
     HashAlgorithmSha512
 };
 
-PLATFORM_EXPORT void computeDigest(HashAlgorithm, const char* digestable, size_t length, DigestValue& digestResult);
+PLATFORM_EXPORT bool computeDigest(HashAlgorithm, const char* digestable, size_t length, DigestValue& digestResult);
 PLATFORM_EXPORT PassOwnPtr<blink::WebCryptoDigestor> createDigestor(HashAlgorithm);
 PLATFORM_EXPORT void finishDigestor(blink::WebCryptoDigestor*, DigestValue& digestResult);
 
 } // namespace WebCore
 
 namespace WTF {
 
 struct DigestValueHash {
     static unsigned hash(const WebCore::DigestValue& v)
     {
@@ skipping 13 matching lines @@
 template <>
 struct DefaultHash<WebCore::HashAlgorithm> {
     typedef IntHash<WebCore::HashAlgorithm> Hash;
 };
 template <>
 struct HashTraits<WebCore::HashAlgorithm> : UnsignedWithZeroKeyHashTraits<WebCore::HashAlgorithm> {
 };
 
 } // namespace WTF
 #endif // SOURCE_PLATFORM_CRYPTO_H_