Move IsPointerConvertible<T, JSONValue> specialization out of TypeTraits.h

Source/platform/JSONValues.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:
  *
  *     * 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 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef JSONValues_h
 #define JSONValues_h
 
 #include "platform/PlatformExport.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/RefCounted.h"
+#include "wtf/TypeTraits.h"
 #include "wtf/Vector.h"
 #include "wtf/text/StringHash.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
+class JSONValue;
+
+} // namespace blink
+
+namespace WTF {
+
+// FIXME: Avoid the need for this global upcasting to JSONValue (for PassRefPtr<T>.)
+// The current CodeGeneratorInspector.py generates code which order sorts its input
+// types and generates forward declarations where needed. But with inline uses
+// of setValue(PassRefPtr<JSONValue>) this is not quite sufficient for the
+// implicit conversion of PassRefPtr<T> to PassRefPtr<JSONValue> for a T that
+// has only been forward declared -- IsPointerConvertible<> doesn't have
+// complete types to work with.
+//
+// Work around that problem here by hackily declaring this global & unsafe
+// specialization.
+//
+// (InspectorTypeBuilder.h is the only piece of code that relies on this specialization.)
+template<typename From> class IsPointerConvertible<From, blink::JSONValue> {
+public:
+    enum {
+        Value = true
+    };
+};
+
+} // namespace WTF
+
+namespace blink {
+
 class JSONArray;
 class JSONObject;
 
 class PLATFORM_EXPORT JSONValue : public RefCounted<JSONValue> {
 public:
     static const int maxDepth = 1000;
 
     JSONValue() : m_type(TypeNull) { }
     virtual ~JSONValue() { }
 
@@ skipping 255 matching lines @@
     using JSONArrayBase::pushArray;
 
     using JSONArrayBase::get;
 
     using JSONArrayBase::begin;
     using JSONArrayBase::end;
 };
 
 } // namespace blink
 
-#endif // !defined(JSONValues_h)
+#endif // JSONValues_h