Support for the new WebCrypto digest by chunks API.

content/child/webcrypto/webcrypto_impl.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_WEBCRYPTO_IMPL_H_
 #define CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "third_party/WebKit/public/platform/WebCrypto.h"
@@ skipping 65 matching lines @@
       const blink::WebCryptoAlgorithm& unwrapped_key_algorithm,
       bool extractable,
       blink::WebCryptoKeyUsageMask usages,
       blink::WebCryptoResult result);
   // This method synchronously computes a digest for the given data, returning
   // |true| if successful and |false| otherwise.
   virtual bool digestSynchronous(const blink::WebCryptoAlgorithmId algorithm_id,
                                  const unsigned char* data,
                                  unsigned int data_size,
                                  blink::WebArrayBuffer& result);
+  // This method returns a digestor object that can be used to synchronously
+  // compute a digest one chunk at a time. Thus, the consume does not need to
+  // hold onto a large buffer with all the data to digest. Chunks can be given
+  // one at a time and the digest will be computed piecemeal. The allocated
+  // WebCrytpoDigestor that is returned by createDigestor must be freed by the
+  // caller.
+  virtual blink::WebCryptoDigestor* createDigestor(
+      const blink::WebCryptoAlgorithmId algorithm_id);

[eroman, 2014/03/26 01:43:54]

IMPORTANT: In the blink interface the input is non-const. This probably needs to
similarly be non-const or maybe it will create an overload rather than
overriding. Worth testing either way.

[jww, 2014/03/26 18:49:40]

Good catch! I ran some tests, and it seems like it overrode it (rather than
overloaded it) anyway, but obviously should match anyway.

 
   virtual bool deserializeKeyForClone(
       const blink::WebCryptoKeyAlgorithm& algorithm,
       blink::WebCryptoKeyType type,
       bool extractable,
       blink::WebCryptoKeyUsageMask usages,
       const unsigned char* key_data,
       unsigned key_data_size,
       blink::WebCryptoKey& key);
 
   virtual bool serializeKeyForClone(const blink::WebCryptoKey& key,
                                     blink::WebVector<unsigned char>& key_data);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WebCryptoImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_IMPL_H_