Add Flex to views::BoxLayout.

ash/system/tray_accessibility.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_accessibility.h"
 
 #include "ash/accessibility_delegate.h"
 #include "ash/metrics/user_metrics_recorder.h"
 #include "ash/shell.h"
 #include "ash/system/tray/hover_highlight_view.h"
@@ skipping 200 matching lines @@
   if (login_ == user::LOGGED_IN_NONE ||
       login_ == user::LOGGED_IN_LOCKED)
     return;
 
   views::View* bottom_row = new View();
   views::BoxLayout* layout = new
       views::BoxLayout(views::BoxLayout::kHorizontal,
                        kTrayMenuBottomRowPadding,
                        kTrayMenuBottomRowPadding,
                        kTrayMenuBottomRowPaddingBetweenItems);
-  layout->set_main_axis_alignment(views::BoxLayout::MAIN_AXIS_ALIGNMENT_FILL);
+  layout->set_default_flex(1);
   bottom_row->SetLayoutManager(layout);
 
   ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
 
   TrayPopupLabelButton* help = new TrayPopupLabelButton(
       this,
       bundle.GetLocalizedString(
           IDS_ASH_STATUS_TRAY_ACCESSIBILITY_LEARN_MORE));
   bottom_row->AddChildView(help);
   help_view_ = help;
@@ skipping 195 matching lines @@
     if (detailed_popup_)
       detailed_popup_->GetWidget()->Close();
     if (detailed_menu_)
       detailed_menu_->GetWidget()->Close();
   }
 
   previous_accessibility_state_ = accessibility_state;
 }
 
 }  // namespace ash