[webcrypto] Check for empty key usages *after* key creation rather than before, to match the spec's…

components/webcrypto/algorithms/hkdf.cc

 // Copyright 2015 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.
 
 #include <openssl/err.h>
 #include <openssl/hkdf.h>
 #include <stdint.h>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 11 matching lines @@
 
 namespace {
 
 const blink::WebCryptoKeyUsageMask kValidUsages =
     blink::WebCryptoKeyUsageDeriveKey | blink::WebCryptoKeyUsageDeriveBits;
 
 class HkdfImplementation : public AlgorithmImplementation {
  public:
   HkdfImplementation() {}
 
-  Status VerifyKeyUsagesBeforeImportKey(
-      blink::WebCryptoKeyFormat format,
-      blink::WebCryptoKeyUsageMask usages) const override {
-    if (format != blink::WebCryptoKeyFormatRaw)
-      return Status::ErrorUnsupportedImportKeyFormat();
-    return CheckSecretKeyCreationUsages(kValidUsages, usages);
+  Status ImportKey(blink::WebCryptoKeyFormat format,
+                   const CryptoData& key_data,
+                   const blink::WebCryptoAlgorithm& algorithm,
+                   bool extractable,
+                   blink::WebCryptoKeyUsageMask usages,
+                   blink::WebCryptoKey* key) const override {
+    switch (format) {
+      case blink::WebCryptoKeyFormatRaw:
+        return ImportKeyRaw(key_data, algorithm, extractable, usages, key);
+      default:
+        return Status::ErrorUnsupportedImportKeyFormat();
+    }
   }
 
   Status ImportKeyRaw(const CryptoData& key_data,
                       const blink::WebCryptoAlgorithm& algorithm,
                       bool extractable,
                       blink::WebCryptoKeyUsageMask usages,
-                      blink::WebCryptoKey* key) const override {
+                      blink::WebCryptoKey* key) const {
+    Status status = CheckKeyCreationUsages(kValidUsages, usages);
+    if (status.IsError())
+      return status;
+
     return CreateWebCryptoSecretKey(
         key_data, blink::WebCryptoKeyAlgorithm::createWithoutParams(
                       blink::WebCryptoAlgorithmIdHkdf),
         extractable, usages, key);
   }
 
   Status DeriveBits(const blink::WebCryptoAlgorithm& algorithm,
                     const blink::WebCryptoKey& base_key,
                     bool has_optional_length_bits,
                     unsigned int optional_length_bits,
@@ skipping 49 matching lines @@
   }
 };
 
 }  // namespace
 
 std::unique_ptr<AlgorithmImplementation> CreateHkdfImplementation() {
   return base::WrapUnique(new HkdfImplementation);
 }
 
 }  // namespace webcrypto