[webcrypto] Implement structured clone of keys (blink-side).

public/platform/WebCryptoKey.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 68 matching lines @@
 // WebCryptoKey is:
 //   * Copiable (cheaply)
 //   * Threadsafe if the embedder's WebCryptoKeyHandle is also threadsafe.
 //
 // The embedder is responsible for creating all WebCryptoKeys, and therefore can
 // safely assume any details regarding the type of the wrapped
 // WebCryptoKeyHandle*.
 //
 // If WebCryptoKey "isNull()" then it is invalid to call any of the other
 // methods on it (other than destruction, assignment, or isNull()).
-//
-// FIXME: Define the interface to use for structured clone.
-//        Cloning across a process boundary will need serialization,
-//        however cloning for in-process workers could just share the same
-//        (threadsafe) handle.
 class WebCryptoKey {
 public:
     ~WebCryptoKey() { reset(); }
 
     WebCryptoKey(const WebCryptoKey& other) { assign(other); }
     WebCryptoKey& operator=(const WebCryptoKey& other)
     {
         assign(other);
         return *this;
     }
@@ skipping 29 matching lines @@
 // Base class for the embedder to define its own opaque key handle. The lifetime
 // of this object is controlled by WebCryptoKey using reference counting.
 class WebCryptoKeyHandle {
 public:
     virtual ~WebCryptoKeyHandle() { }
 };
 
 } // namespace blink
 
 #endif