Simplify TransferMode and Color types.

sky/engine/core/painting/TransferMode.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SKY_ENGINE_CORE_PAINTING_TRANSFERMODE_H_
 #define SKY_ENGINE_CORE_PAINTING_TRANSFERMODE_H_
 
 #include "sky/engine/core/painting/Rect.h"
 #include "sky/engine/tonic/dart_wrappable.h"
 #include "sky/engine/wtf/PassRefPtr.h"
 #include "sky/engine/wtf/RefCounted.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 
 namespace blink {
 
-class TransferMode {
- public:
-  SkXfermode::Mode sk_mode;
-};
+class TransferMode {};
 
-template<>
-struct DartConverter<TransferMode, void> {
-  static TransferMode FromArgumentsWithNullCheck(Dart_NativeArguments args,
-                                                 int index,
-                                                 Dart_Handle& exception);
+template <>
+struct DartConverter<TransferMode> {
+  static SkXfermode::Mode FromArgumentsWithNullCheck(Dart_NativeArguments args,
+                                                     int index,
+                                                     Dart_Handle& exception);
 };
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_PAINTING_TRANSFERMODE_H_