[webcrypto] Make all of the crypto.subtle method failures asynchronous.

Source/modules/crypto/Key.h

 /*
  * 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 25 matching lines @@
 #include "modules/crypto/NormalizeAlgorithm.h"
 #include "public/platform/WebCryptoKey.h"
 #include "wtf/Forward.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
 class Algorithm;
-class ExceptionState;
+class CryptoResult;
 
 class Key : public RefCountedWillBeGarbageCollectedFinalized<Key>,  public ScriptWrappable {
     DECLARE_GC_INFO;
 public:
     static PassRefPtrWillBeRawPtr<Key> create(const blink::WebCryptoKey& key)
     {
         return adoptRefWillBeNoop(new Key(key));
     }
 
     ~Key();
 
     String type() const;
     bool extractable() const;
     Algorithm* algorithm();
     Vector<String> usages() const;
 
     const blink::WebCryptoKey& key() const { return m_key; }
 
     // If the key cannot be used with the indicated algorithm, returns false
-    // and fills the provided String with error details.
-    bool canBeUsedForAlgorithm(const blink::WebCryptoAlgorithm&, AlgorithmOperation, String&) const;
+    // and completes the CryptoResult with an error.
+    bool canBeUsedForAlgorithm(const blink::WebCryptoAlgorithm&, AlgorithmOperation, CryptoResult*) const;
 
-    static bool parseFormat(const String&, blink::WebCryptoKeyFormat&, ExceptionState&);
-    static bool parseUsageMask(const Vector<String>&, blink::WebCryptoKeyUsageMask&, ExceptionState&);
+    // On failure, these return false and complete the CryptoResult with an error.
+    static bool parseFormat(const String&, blink::WebCryptoKeyFormat&, CryptoResult*);
+    static bool parseUsageMask(const Vector<String>&, blink::WebCryptoKeyUsageMask&, CryptoResult*);
 
     void trace(Visitor*);
 
 protected:
     explicit Key(const blink::WebCryptoKey&);
 
     const blink::WebCryptoKey m_key;
     RefPtrWillBeMember<Algorithm> m_algorithm;
 };
 
 } // namespace WebCore
 
 #endif