(Merge to M-51) Revise the shelf alignment locking mechanism.

ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc

 // Copyright 2014 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/chromeos/virtual_keyboard/virtual_keyboard_tray.h"
 
 #include "ash/keyboard/keyboard_ui.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_constants.h"
+#include "ash/shelf/shelf_util.h"
 #include "ash/shell.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/system_tray_notifier.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_utils.h"
 #include "grit/ash_resources.h"
 #include "grit/ash_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/events/event.h"
@@ skipping 33 matching lines @@
   const gfx::ImageSkia image = button_->GetImage(
       views::CustomButton::STATE_NORMAL);
   int top_padding = (kTrayBarButtonWidth - image.height()) / 2;
   int left_padding = (kTrayBarButtonWidth - image.width()) / 2;
   int bottom_padding = kTrayBarButtonWidth - image.height() - top_padding;
   int right_padding = kTrayBarButtonWidth - image.width() - left_padding;
 
   // Square up the padding if horizontally aligned. Avoid extra padding when
   // vertically aligned as the button would violate the width constraint on the
   // shelf.
-  if (alignment == SHELF_ALIGNMENT_BOTTOM) {
+  if (IsHorizontalAlignment(alignment)) {
     gfx::Insets insets = button_->GetInsets();
     int additional_padding = std::max(0, top_padding - left_padding);
     left_padding += additional_padding;
     right_padding += additional_padding;
   }
 
   button_->SetBorder(views::Border::CreateEmptyBorder(
       top_padding,
       left_padding,
       bottom_padding,
@@ skipping 22 matching lines @@
                                         const ui::Event& event) {
   DCHECK_EQ(button_, sender);
   PerformAction(event);
 }
 
 void VirtualKeyboardTray::OnKeyboardEnabledStateChanged(bool new_value) {
   SetVisible(Shell::GetInstance()->keyboard_ui()->IsEnabled());
 }
 
 }  // namespace ash