[webcrypto] Reject failed operations with a DOMException rather than null.

Source/modules/crypto/Key.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 150 matching lines @@
         blink::WebCryptoKeyUsage usage = keyUsageMappings[i].value;
         if (m_key.usages() & usage)
             result.append(keyUsageToString(usage));
     }
     return result;
 }
 
 bool Key::canBeUsedForAlgorithm(const blink::WebCryptoAlgorithm& algorithm, AlgorithmOperation op, CryptoResult* result) const
 {
     if (!(m_key.usages() & toKeyUsage(op))) {
-        result->completeWithError("key.usages does not permit this operation");
+        result->completeWithError(blink::WebCryptoErrorTypeInvalidAccess, "key.usages does not permit this operation");
         return false;
     }
 
     if (m_key.algorithm().id() != algorithm.id()) {
-        result->completeWithError("key.algorithm does not match that of operation");
+        result->completeWithError(blink::WebCryptoErrorTypeInvalidAccess, "key.algorithm does not match that of operation");
         return false;
     }
 
     return true;
 }
 
 bool Key::parseFormat(const String& formatString, blink::WebCryptoKeyFormat& format, CryptoResult* result)
 {
     // There are few enough values that testing serially is fast enough.
     if (formatString == "raw") {
         format = blink::WebCryptoKeyFormatRaw;
         return true;
     }
     if (formatString == "pkcs8") {
         format = blink::WebCryptoKeyFormatPkcs8;
         return true;
     }
     if (formatString == "spki") {
         format = blink::WebCryptoKeyFormatSpki;
         return true;
     }
     if (formatString == "jwk") {
         format = blink::WebCryptoKeyFormatJwk;
         return true;
     }
 
-    result->completeWithError("Invalid keyFormat argument");
+    result->completeWithError(blink::WebCryptoErrorTypeSyntax, "Invalid keyFormat argument");
     return false;
 }
 
 bool Key::parseUsageMask(const Vector<String>& usages, blink::WebCryptoKeyUsageMask& mask, CryptoResult* result)
 {
     mask = 0;
     for (size_t i = 0; i < usages.size(); ++i) {
         blink::WebCryptoKeyUsageMask usage = keyUsageStringToMask(usages[i]);
         if (!usage) {
-            result->completeWithError("Invalid keyUsages argument");
+            result->completeWithError(blink::WebCryptoErrorTypeSyntax, "Invalid keyUsages argument");
             return false;
         }
         mask |= usage;
     }
     return true;
 }
 
 void Key::trace(Visitor* visitor)
 {
     visitor->trace(m_algorithm);
 }
 
 } // namespace WebCore