Refactor the interface for generating keys.

content/child/webcrypto/openssl/sym_key_openssl.cc

Index: content/child/webcrypto/openssl/sym_key_openssl.cc
diff --git a/content/child/webcrypto/openssl/sym_key_openssl.cc b/content/child/webcrypto/openssl/sym_key_openssl.cc
index e07db69ee7f3f6e96feb5cdcfe34913da8f0f908..21af6831c4f6efc8f4f53cb87105789e9d031339 100644
--- a/content/child/webcrypto/openssl/sym_key_openssl.cc
+++ b/content/child/webcrypto/openssl/sym_key_openssl.cc
@@ -8,6 +8,7 @@
 #include <openssl/rand.h>
 
 #include "content/child/webcrypto/crypto_data.h"
+#include "content/child/webcrypto/generate_key_result.h"
 #include "content/child/webcrypto/openssl/key_openssl.h"
 #include "content/child/webcrypto/status.h"
 #include "crypto/openssl_util.h"
@@ -21,7 +22,7 @@ Status GenerateSecretKeyOpenSsl(const blink::WebCryptoKeyAlgorithm& algorithm,
                                 bool extractable,
                                 blink::WebCryptoKeyUsageMask usage_mask,
                                 unsigned keylen_bytes,
-                                blink::WebCryptoKey* key) {
+                                GenerateKeyResult* result) {
   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
 
   std::vector<unsigned char> random_bytes(keylen_bytes, 0);
@@ -31,7 +32,8 @@ Status GenerateSecretKeyOpenSsl(const blink::WebCryptoKeyAlgorithm& algorithm,
       return Status::OperationError();
   }
 
-  *key =
+  result->set_type(GenerateKeyResult::TYPE_SECRET_KEY);
+  *result->mutable_secret_key() =
       blink::WebCryptoKey::create(new SymKeyOpenSsl(CryptoData(random_bytes)),
                                   blink::WebCryptoKeyTypeSecret,
                                   extractable,