Have Dictionary use V8TRYCATCH_FOR_V8STRINGRESOURCE() macro

Source/bindings/v8/V8StringResource.h

 /*
  * Copyright (C) 2009 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
@@ skipping 163 matching lines @@
 class V8StringResource {
 public:
     V8StringResource(v8::Handle<v8::Value> object)
         : m_v8Object(object)
         , m_mode(Externalize)
         , m_string()
     {
     }
 
     bool prepare();
-    operator String() { return toString<String>(); }
-    operator AtomicString() { return toString<AtomicString>(); }
+    operator String() const { return toString<String>(); }
+    operator AtomicString() const { return toString<AtomicString>(); }
 
 private:
     bool prepareBase()
     {
         if (m_v8Object.IsEmpty())
             return true;
 
         if (LIKELY(m_v8Object->IsString()))
             return true;
 
@@ skipping 13 matching lines @@
         return true;
     }
 
     void setString(const String& string)
     {
         m_string = string;
         m_v8Object.Clear(); // To signal that String is ready.
     }
 
     template <class StringType>
-    StringType toString()
+    StringType toString() const
     {
         if (LIKELY(!m_v8Object.IsEmpty()))
-            return v8StringToWebCoreString<StringType>(m_v8Object.As<v8::String>(), m_mode);
+            return v8StringToWebCoreString<StringType>(const_cast<v8::Handle<v8::Value>*>(&m_v8Object)->As<v8::String>(), m_mode);
 
         return StringType(m_string);
     }
 
     v8::Handle<v8::Value> m_v8Object;
     ExternalMode m_mode;
     String m_string;
 };
 
 template<> inline bool V8StringResource<DefaultMode>::prepare()
@@ skipping 15 matching lines @@
     if (m_v8Object.IsEmpty() || m_v8Object->IsNull() || m_v8Object->IsUndefined()) {
         setString(String());
         return true;
     }
     return prepareBase();
 }
 
 } // namespace WebCore
 
 #endif // V8StringResource_h