Make back button on stocks app search bar the accent color

sky/sdk/example/stocks/lib/stock_home.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 'package:sky/editing/input.dart';
 import 'package:sky/animation/animation_performance.dart';
 import 'package:sky/widgets/animated_component.dart';
 import 'package:sky/widgets/animated_container.dart';
 import 'package:sky/theme/colors.dart' as colors;
 import 'package:sky/widgets/basic.dart';
@@ skipping 234 matching lines @@
         setState(() { selectedTabIndex = tabIndex; } );
       }
     );
   }
 
   // TODO(abarth): Should we factor this into a SearchBar in the framework?
   Widget buildSearchBar() {
     return new ToolBar(
       left: new IconButton(
         icon: "navigation/arrow_back",
-        onPressed: _handleSearchEnd),
+        color: Theme.of(this).accentColor,
+        onPressed: _handleSearchEnd
+      ),
       center: new Input(
         focused: true,
         placeholder: 'Search stocks',
-        onChanged: _handleSearchQueryChanged),
+        onChanged: _handleSearchQueryChanged
+      ),
       backgroundColor: Theme.of(this).canvasColor
     );
   }
 
   void _handleUndo() {
     setState(() {
       _snackbarTransform = null;
     });
   }
 
@@ skipping 48 matching lines @@
         body: buildTabNavigator(),
         snackBar: buildSnackBar(),
         floatingActionButton: buildFloatingActionButton(),
         drawer: _drawerShowing ? buildDrawer() : null
       ),
     ];
     addMenuToOverlays(overlays);
     return new Stack(overlays);
   }
 }