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

Source/bindings/templates/dictionary_v8.h

Index: Source/bindings/templates/dictionary_v8.h
diff --git a/Source/bindings/templates/dictionary_v8.h b/Source/bindings/templates/dictionary_v8.h
index 26eb3679b9c1d5f7124f6c84b4a8b0a99318c4cc..b18460906c4c75772960a715046259efc2532fb0 100644
--- a/Source/bindings/templates/dictionary_v8.h
+++ b/Source/bindings/templates/dictionary_v8.h
@@ -17,7 +17,7 @@ class ExceptionState;
 
 class {{v8_class}} {
 public:
-    static void toImpl(v8::Isolate*, v8::Local<v8::Value>, {{cpp_class}}&, ExceptionState&);
+    static bool toImpl(v8::Isolate*, v8::Local<v8::Value>, {{cpp_class}}&, ExceptionState&);
 };
 
 v8::Local<v8::Value> toV8(const {{cpp_class}}&, v8::Local<v8::Object>, v8::Isolate*);