Support for the new WebCrypto digest by chunks API.

content/child/webcrypto/platform_crypto.h

Index: content/child/webcrypto/platform_crypto.h
diff --git a/content/child/webcrypto/platform_crypto.h b/content/child/webcrypto/platform_crypto.h
index 8c28e3f02b9058427f474f89f38b8ae6a4f8e72e..8a090e22da24329e906d90588bbb1fd7764d9e8a 100644
--- a/content/child/webcrypto/platform_crypto.h
+++ b/content/child/webcrypto/platform_crypto.h
@@ -91,6 +91,9 @@ Status DigestSha(blink::WebCryptoAlgorithmId algorithm,
                  const CryptoData& data,
                  blink::WebArrayBuffer* buffer);
 
+blink::WebCryptoDigestor* CreateDigestor(

[eroman, 2014/03/25 23:26:23]

* Please add a precondition comment saying that algorithm_id is for a hash.
* Can you change the signature to be so either it returns a scoped_ptr<>, or it
takes a scoped_ptr<>* as input?

[jww, 2014/03/26 00:42:31]

Done.

+    blink::WebCryptoAlgorithmId algorithm_id);
+
 // Preconditions:
 //  * |key| is non-null.
 //  * |hash| is a digest algorithm.