Add Flex to views::BoxLayout.

ash/system/tray/system_tray_bubble.cc

 // Copyright (c) 2012 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.
 
 #include "ash/system/tray/system_tray_bubble.h"
 
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/system_tray_item.h"
@@ skipping 35 matching lines @@
                          bool draw_border)
       : hover_(false),
         change_background_(change_background) {
     set_notify_enter_exit_on_child(true);
     if (draw_border) {
       SetBorder(
           views::Border::CreateSolidSidedBorder(0, 0, 1, 0, kBorderLightColor));
     }
     views::BoxLayout* layout = new views::BoxLayout(
         views::BoxLayout::kVertical, 0, 0, 0);
-    layout->set_main_axis_alignment(views::BoxLayout::MAIN_AXIS_ALIGNMENT_FILL);
+    layout->SetDefaultFlex(1);
     SetLayoutManager(layout);
     SetPaintToLayer(view->layer() != NULL);
     if (view->layer())
       SetFillsBoundsOpaquely(view->layer()->fills_bounds_opaquely());
     AddChildView(view);
     SetVisible(view->visible());
   }
 
   virtual ~TrayPopupItemContainer() {}
 
@@ skipping 316 matching lines @@
     // 2 items, which are the bottom header row and the one just above it.
     bubble_view_->AddChildView(new TrayPopupItemContainer(
         item_views[i], is_default_bubble,
         is_default_bubble && (i < item_views.size() - 2)));
   }
   if (focus_view)
     focus_view->RequestFocus();
 }
 
 }  // namespace ash