Move createClosure from V8PromiseCustom.cpp to V8Binding.h

Source/bindings/v8/V8Binding.h

Index: Source/bindings/v8/V8Binding.h
diff --git a/Source/bindings/v8/V8Binding.h b/Source/bindings/v8/V8Binding.h
index ad57ae15830bbf3751e4701907a327a61d407a55..140d4a15bb664daba5a9c9f11beec6e0d130d3ef 100644
--- a/Source/bindings/v8/V8Binding.h
+++ b/Source/bindings/v8/V8Binding.h
@@ -579,6 +579,12 @@ namespace WebCore {
         return *handle;
     }
 
+    // Attaches |environment| to |function| and returns it.
+    inline v8::Local<v8::Function> createClosure(v8::FunctionCallback function, v8::Handle<v8::Value> environment)
+    {
+        return v8::FunctionTemplate::New(function, environment)->GetFunction();
+    }
+
 } // namespace WebCore
 
 #endif // V8Binding_h