[webcrypto] Make WebCryptoAlgorithm "nullable".

Source/core/platform/chromium/support/WebCryptoAlgorithm.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 36 matching lines @@
 
     WebCryptoAlgorithmId id;
     OwnPtr<WebCryptoAlgorithmParams> params;
 };
 
 WebCryptoAlgorithm::WebCryptoAlgorithm(WebCryptoAlgorithmId id, PassOwnPtr<WebCryptoAlgorithmParams> params)
     : m_private(adoptRef(new WebCryptoAlgorithmPrivate(id, params)))
 {
 }
 
+WebCryptoAlgorithm WebCryptoAlgorithm::createNull()
+{
+    return WebCryptoAlgorithm();
+}
+
 WebCryptoAlgorithm WebCryptoAlgorithm::adoptParamsAndCreate(WebCryptoAlgorithmId id, WebCryptoAlgorithmParams* params)
 {
     return WebCryptoAlgorithm(id, adoptPtr(params));
 }
 
+bool WebCryptoAlgorithm::isNull() const
+{
+    return m_private.isNull();
+}
+
 WebCryptoAlgorithmId WebCryptoAlgorithm::id() const
 {
+    ASSERT(!isNull());
     return m_private->id;
 }
 
 WebCryptoAlgorithmParamsType WebCryptoAlgorithm::paramsType() const
 {
+    ASSERT(!isNull());
     if (!m_private->params)
         return WebCryptoAlgorithmParamsTypeNone;
     return m_private->params->type();
 }
 
 const WebCryptoAesCbcParams* WebCryptoAlgorithm::aesCbcParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeAesCbcParams)
         return static_cast<WebCryptoAesCbcParams*>(m_private->params.get());
     return 0;
 }
 
 const WebCryptoAesKeyGenParams* WebCryptoAlgorithm::aesKeyGenParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeAesKeyGenParams)
         return static_cast<WebCryptoAesKeyGenParams*>(m_private->params.get());
     return 0;
 }
 
 const WebCryptoHmacParams* WebCryptoAlgorithm::hmacParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeHmacParams)
         return static_cast<WebCryptoHmacParams*>(m_private->params.get());
     return 0;
 }
 
 const WebCryptoHmacKeyParams* WebCryptoAlgorithm::hmacKeyParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeHmacKeyParams)
         return static_cast<WebCryptoHmacKeyParams*>(m_private->params.get());
     return 0;
 }
 
 const WebCryptoRsaSsaParams* WebCryptoAlgorithm::rsaSsaParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeRsaSsaParams)
         return static_cast<WebCryptoRsaSsaParams*>(m_private->params.get());
     return 0;
 }
 
 const WebCryptoRsaKeyGenParams* WebCryptoAlgorithm::rsaKeyGenParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeRsaKeyGenParams)
         return static_cast<WebCryptoRsaKeyGenParams*>(m_private->params.get());
     return 0;
 }
 
 const WebCryptoAesGcmParams* WebCryptoAlgorithm::aesGcmParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeAesGcmParams)
         return static_cast<WebCryptoAesGcmParams*>(m_private->params.get());
     return 0;
 }
 
 const WebCryptoRsaOaepParams* WebCryptoAlgorithm::rsaOaepParams() const
 {
+    ASSERT(!isNull());
     if (paramsType() == WebCryptoAlgorithmParamsTypeRsaOaepParams)
         return static_cast<WebCryptoRsaOaepParams*>(m_private->params.get());
     return 0;
 }
 
 void WebCryptoAlgorithm::assign(const WebCryptoAlgorithm& other)
 {
     m_private = other.m_private;
 }
 
 void WebCryptoAlgorithm::reset()
 {
     m_private.reset();
 }
 
 } // namespace WebKit