Fix all the components to pick the right colours from the theme.

sky/sdk/lib/widgets/popup_menu_item.dart

Index: sky/sdk/lib/widgets/popup_menu_item.dart
diff --git a/sky/sdk/lib/widgets/popup_menu_item.dart b/sky/sdk/lib/widgets/popup_menu_item.dart
index 1a183b1b50c9cbef250237668de3127406930309..42c0ce40ad602595fbd0c8623c87914ff8b626c5 100644
--- a/sky/sdk/lib/widgets/popup_menu_item.dart
+++ b/sky/sdk/lib/widgets/popup_menu_item.dart
@@ -2,8 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import '../painting/text_style.dart';
 import 'basic.dart';
+import 'default_text_style.dart';
 import 'ink_well.dart';
+import 'theme.dart';
 
 class PopupMenuItem extends Component {
   PopupMenuItem({ String key, this.child, this.opacity}) : super(key: key);
@@ -11,6 +14,8 @@ class PopupMenuItem extends Component {
   final Widget child;
   final double opacity;
 
+  TextStyle get textStyle => Theme.of(this).text.subhead;
+
   Widget build() {
     return new Opacity(
       opacity: opacity,
@@ -18,7 +23,10 @@ class PopupMenuItem extends Component {
         child: new Container(
           constraints: const BoxConstraints(minWidth: 112.0),
           padding: const EdgeDims.all(16.0),
-          child: child
+          child: new DefaultTextStyle(
+            style: textStyle,
+            child: child
+          )
         )
       )
     );