[webcrypto] Set the error type for failures.

content/child/webcrypto/jwk.cc

Index: content/child/webcrypto/jwk.cc
diff --git a/content/child/webcrypto/jwk.cc b/content/child/webcrypto/jwk.cc
index 4692d321abff4e327448d3b81e4ef41f8a0b66b5..b0b5cd74bb0bb0344a9a05454c1043ee04a6966b 100644
--- a/content/child/webcrypto/jwk.cc
+++ b/content/child/webcrypto/jwk.cc
@@ -794,7 +794,7 @@ Status ExportKeyJwk(const blink::WebCryptoKey& key,
                     blink::WebArrayBuffer* buffer) {
   DCHECK(key.extractable());
   base::DictionaryValue jwk_dict;
-  Status status = Status::Error();
+  Status status = Status::OperationError();

[Ryan Sleevi, 2014/04/22 23:45:50]

What part of the spec led you to believe this was the right error? I can't find
any support for it. Then again, this value is never returned - so seems worth
documenting that it's a dummy value? Or just use Status::Error?

[eroman, 2014/04/23 00:11:30]

I renamed Status::Error() to Status::OperationError(), since there isn't an
equivalent generic error for the exceptions.

 
   switch (key.type()) {
     case blink::WebCryptoKeyTypeSecret: {