IDL: Drop value conversion (V8 -> C++) macros from generated code

Source/bindings/core/v8/V8StringResource.h

Index: Source/bindings/core/v8/V8StringResource.h
diff --git a/Source/bindings/core/v8/V8StringResource.h b/Source/bindings/core/v8/V8StringResource.h
index 6539094c5f3a28547615415a4093afe4d5f531de..0c85264241a56c75fffc8caf6c3be67989b7ef9c 100644
--- a/Source/bindings/core/v8/V8StringResource.h
+++ b/Source/bindings/core/v8/V8StringResource.h
@@ -179,6 +179,12 @@ public:
     {
     }
 
+    V8StringResource(const String& string)
+        : m_mode(Externalize)
+        , m_string(string)
+    {
+    }
+
     void operator=(v8::Handle<v8::Value> object)
     {
         m_v8Object = object;