Improve stocks2 performance

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 87 matching lines @@
       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
     );
   }
 
   bool operator ==(other) {
+    if (identical(this, other))
+      return true;
     return other is TextStyle &&
       color == other.color &&
       fontFamily == other.fontFamily && 
       fontSize == other.fontSize &&
       fontWeight == other.fontWeight &&
       textAlign == other.textAlign && 
       decoration == other.decoration &&
       decorationColor == other.decorationColor &&
       decorationStyle == other.decorationStyle;
   }
@@ skipping 66 matching lines @@
       result.add('${prefix}decoration: ${_decorationToString()}');
     if (decorationColor != null)
       result.add('${prefix}decorationColor: $decorationColor');
     if (decorationStyle != null)
       result.add('${prefix}decorationStyle: $decorationStyle');
     if (result.isEmpty)
       return '${prefix}<no style specified>';
     return result.join('\n');
   }
 }