Refactor WebCrypto code

content/child/webcrypto/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.
 
 #ifndef CONTENT_CHILD_WEBCRYPTO_PLATFORM_CRYPTO_H_
 #define CONTENT_CHILD_WEBCRYPTO_PLATFORM_CRYPTO_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 206 matching lines @@
                            const CryptoData& private_exponent,
                            const CryptoData& prime1,
                            const CryptoData& prime2,
                            const CryptoData& exponent1,
                            const CryptoData& exponent2,
                            const CryptoData& coefficient,
                            blink::WebCryptoKey* key);
 
 // Note that this may be called from target Blink thread.
 // Preconditions:
+//  * algorithm is for an asymmetric algorithm
 //  * usage_mask makes sense for the algorithm.
+//  * key_data is not zero-length.
 Status ImportKeySpki(const blink::WebCryptoAlgorithm& algorithm,
                      const CryptoData& key_data,
                      bool extractable,
                      blink::WebCryptoKeyUsageMask usage_mask,
                      blink::WebCryptoKey* key);
 
 // Note that this may be called from target Blink thread.
 // Preconditions:
+//  * algorithm is for an asymmetric algorithm
 //  * usage_mask makes sense for the algorithm.
+//  * key_data is not zero-length.
 Status ImportKeyPkcs8(const blink::WebCryptoAlgorithm& algorithm,
                       const CryptoData& key_data,
                       bool extractable,
                       blink::WebCryptoKeyUsageMask usage_mask,
                       blink::WebCryptoKey* key);
 
 // Preconditions:
 //  * |key| is non-null.
 Status ExportKeyRaw(SymKey* key, std::vector<uint8>* buffer);
 
@@ skipping 36 matching lines @@
                            const CryptoData& data,
                            std::vector<uint8>* buffer);
 
 }  // namespace platform
 
 }  // namespace webcrypto
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_PLATFORM_CRYPTO_H_