Material light and dark themes for Sky widgets

sky/sdk/lib/painting/text_style.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.
 
 import 'dart:sky';
 
 enum FontWeight {
   w100,
   w200,
   w300,
@@ skipping 56 matching lines @@
   final String fontFamily;
   final double fontSize; // in pixels
   final FontWeight fontWeight;
   final TextAlign textAlign;
   final List<TextDecoration> decoration; // TODO(ianh): Switch this to a Set<> once Dart supports constant Sets
   final Color decorationColor;
   final TextDecorationStyle decorationStyle;
 
   TextStyle copyWith({
     Color color,
+    String fontFamily,
     double fontSize,
     FontWeight fontWeight,
     TextAlign textAlign,
     TextDecoration decoration,
     Color decorationColor,
     TextDecorationStyle decorationStyle
   }) {
     return new TextStyle(
       color: color != null ? color : this.color,
       fontFamily: fontFamily != null ? fontFamily : this.fontFamily,
       fontSize: fontSize != null ? fontSize : this.fontSize,
       fontWeight: fontWeight != null ? fontWeight : this.fontWeight,
       textAlign: textAlign != null ? textAlign : this.textAlign,
       decoration: decoration != null ? decoration : this.decoration,
       decorationColor: decorationColor != null ? decorationColor : this.decorationColor,
       decorationStyle: decorationStyle != null ? decorationStyle : this.decorationStyle
     );
   }
 
   static String _colorToCSSString(Color color) {
     return 'rgba(${color.red}, ${color.green}, ${color.blue}, ${color.alpha / 255.0})';
   }
 
+  TextStyle merge(TextStyle other) {
+    return copyWith(
+      color: other.color,
+      fontFamily: other.fontFamily,
+      fontSize: other.fontSize,
+      fontWeight: other.fontWeight,
+      textAlign: other.textAlign,
+      decoration: other.decoration,
+      decorationColor: other.decorationColor,
+      decorationStyle: other.decorationStyle
+    );
+  }
+
   static String _fontFamilyToCSSString(String fontFamily) {
     // TODO(hansmuller): escape the fontFamily string.
     return fontFamily;
   }
 
   static String _decorationToCSSString(List<TextDecoration> decoration) {
     assert(decoration != null);
     const toCSS = const <TextDecoration, String>{
       TextDecoration.none: 'none',
       TextDecoration.underline: 'underline',
@@ skipping 99 matching lines @@
       result.add('${prefix}decoration: $decoration');
     if (decorationColor != null)
       result.add('${prefix}decorationColor: $decorationColor');
     if (decorationStyle != null)
       result.add('${prefix}decorationStyle: $decorationStyle');
     if (result.isEmpty)
       return '${prefix}<no style specified>';
     return result.join('\n');
   }
 }