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..a8c58cd01100583ec329aa23f21b04b57eb0f5d1 100644
--- a/Source/bindings/core/v8/V8StringResource.h
+++ b/Source/bindings/core/v8/V8StringResource.h
@@ -179,14 +179,16 @@ public:
     {
     }
 
-    void operator=(v8::Handle<v8::Value> object)
+    V8StringResource& operator=(v8::Handle<v8::Value> object)
     {
         m_v8Object = object;
+        return *this;
     }
 
-    void operator=(const String& string)
+    V8StringResource& operator=(const String& string)
     {
         setString(string);
+        return *this;
     }
 
     void operator=(std::nullptr_t)