Split Dictionary's get and convert into DictionaryHelper.

Source/bindings/core/v8/DictionaryHelperForBindings.h

+/*
+ * Copyright (C) 2010 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:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef DictionaryHelperForBindings_h
+#define DictionaryHelperForBindings_h
+
+#include "Source/bindings/core/v8/Dictionary.h"
+
+namespace WebCore {
+
+template <typename T>
+struct DictionaryHelperTraits {
+};
+
+template <template <typename> class PointerType, typename T>
+bool DictionaryHelper::get(const Dictionary& dictionary, const String& key, PointerType<T>& value)
+{
+    v8::Local<v8::Value> v8Value;
+    if (!dictionary.get(key, v8Value))
+        return false;
+
+    value = DictionaryHelperTraits<T>::type::toNativeWithTypeCheck(dictionary.isolate(), v8Value);
+    return true;
+}
+
+template <template <typename> class PointerType, typename T>
+bool DictionaryHelper::convert(const Dictionary& dictionary, Dictionary::ConversionContext& context, const String& key, PointerType<T>& value)
+{
+    Dictionary::ConversionContextScope scope(context);
+
+    if (!DictionaryHelper::get(dictionary, key, value))
+        return true;
+
+    if (value)
+        return true;
+
+    v8::Local<v8::Value> v8Value;
+    dictionary.get(key, v8Value);
+    if (context.isNullable() && WebCore::isUndefinedOrNull(v8Value))
+        return true;
+
+    context.throwTypeError(ExceptionMessages::incorrectPropertyType(key, "does not have a " + context.typeName() + " type."));
+    return false;
+}
+
+} // namespace WebCore
+
+#endif // DictionaryHelperForBindings_h