Only Firefox needs the vendor prefix. All other browsers have both (webkit browsers) or the unprefi…

tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. 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 $LIBRARYNAME;
 
 $(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   factory $CLASSNAME() => new CssStyleDeclaration.css('');
 
   factory $CLASSNAME.css(String css) {
@@ skipping 900 matching lines @@
   /** Gets the value of "box-shadow" */
   String get boxShadow =>
     getPropertyValue('box-shadow');
 
   /** Sets the value of "box-shadow" */
   void set boxShadow(String value) {
     setProperty('box-shadow', value, '');
   }
 
   /** Gets the value of "box-sizing" */
-  String get boxSizing =>
-    getPropertyValue('${Device.cssPrefix}box-sizing');
+  String get boxSizing => Device.isFirefox ? 
+      getPropertyValue('${Device.cssPrefix}box-sizing') : 
+      getPropertyValue('box-sizing');
 
   /** Sets the value of "box-sizing" */
   void set boxSizing(String value) {
-    setProperty('${Device.cssPrefix}box-sizing', value, '');
+    if (Device.isFirefox) {

[Jennifer Messerly, 2013/07/19 21:09:20]

presumably Firefox will implement this natively someday, and Dart code compiled
now would be broken. Perhaps the logic should get/set both properties?

+      setProperty('${Device.cssPrefix}box-sizing', value, '');
+    } else {
+      setProperty('box-sizing', value, '');
+    }
   }
 
   /** Gets the value of "caption-side" */
   String get captionSide =>
     getPropertyValue('caption-side');
 
   /** Sets the value of "caption-side" */
   void set captionSide(String value) {
     setProperty('caption-side', value, '');
   }
@@ skipping 2276 matching lines @@
 
   /** Gets the value of "zoom" */
   String get zoom =>
     getPropertyValue('zoom');
 
   /** Sets the value of "zoom" */
   void set zoom(String value) {
     setProperty('zoom', value, '');
   }
 }