Change the ColorFilter constructor to ColorFilter.Mode, in case we want to add

more ColorFilter types.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1163373007.

engine/core/core.gni

@@ -1170,6 +1170,7 @@ core_idl_files = get_path_info([
 
 core_dart_files = get_path_info([
                                   "painting/Color.dart",
+                                  "painting/ColorFilter.dart",
                                   "painting/Gradient.dart",
                                   "painting/MaskFilter.dart",
                                   "painting/PaintingStyle.dart",

engine/core/painting/ColorFilter.dart

+// 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.
+
+part of dart.sky;
+
+/// Extends the generated _ColorFilter interface via the PrivateDart attribute.
+class ColorFilter extends _ColorFilter {
+  // This is the only ColorFilter type we need, but use a named constructor so
+  // we can add more in the future.
+  ColorFilter.Mode(Color color, TransferMode transferMode)
+      : super(color, transferMode) {}
+}

engine/core/painting/ColorFilter.idl

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 [
+  PrivateDart,
   Constructor(Color color, TransferMode transferMode),
 ] interface ColorFilter {
 };

examples/game/lib/sprite_node.dart

@@ -52,7 +52,7 @@ class SpriteNode extends TransformNode {
       Paint paint = new Paint();
       paint.setARGB((255.0*_opacity).toInt(), 255, 255, 255);
       if (colorOverlay != null) {
-        paint.setColorFilter(new ColorFilter(colorOverlay, TransferMode.srcATopMode));
+        paint.setColorFilter(new ColorFilter.Mode(colorOverlay, TransferMode.srcATopMode));
       }
       if (transferMode != null) {
         paint.setTransferMode(transferMode);
@@ -68,4 +68,4 @@ class SpriteNode extends TransformNode {
     }
   }
   
-}
\ No newline at end of file
+}

examples/raw/painting.sky

@@ -56,8 +56,8 @@ void main() {
             (Paint layerPaint) {
           layerPaint.color = const Color.fromARGB(128, 255, 255, 0);
           layerPaint.setColorFilter(
-              new ColorFilter(const Color.fromARGB(128, 0, 0, 255),
-                              TransferMode.srcInMode));
+              new ColorFilter.Mode(const Color.fromARGB(128, 0, 0, 255),
+                                   TransferMode.srcInMode));
           layerPaint.setMaskFilter(
               new MaskFilter.Blur(BlurStyle.normal, 3.0, highQuality: true));
         })