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

ash/system/overview/overview_button_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/overview/overview_button_tray.h"
 
 #include "ash/session/session_state_delegate.h"
 #include "ash/shelf/shelf_types.h"
+#include "ash/shelf/shelf_util.h"
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/tray_utils.h"
 #include "ash/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/wm/overview/window_selector_controller.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/views/border.h"
@@ skipping 81 matching lines @@
 
 void OverviewButtonTray::SetShelfAlignment(ShelfAlignment alignment) {
   if (alignment == shelf_alignment())
     return;
 
   TrayBackgroundView::SetShelfAlignment(alignment);
   SetIconBorderForShelfAlignment();
 }
 
 void OverviewButtonTray::SetIconBorderForShelfAlignment() {
-  if (shelf_alignment() == SHELF_ALIGNMENT_BOTTOM) {
+  if (IsHorizontalAlignment(shelf_alignment())) {
     icon_->SetBorder(views::Border::CreateEmptyBorder(
         kHorizontalShelfVerticalPadding,
         kHorizontalShelfHorizontalPadding,
         kHorizontalShelfVerticalPadding,
         kHorizontalShelfHorizontalPadding));
   } else {
     icon_->SetBorder(views::Border::CreateEmptyBorder(
         kVerticalShelfVerticalPadding,
         kVerticalShelfHorizontalPadding,
         kVerticalShelfVerticalPadding,
@@ skipping 14 matching lines @@
       shell->maximize_mode_controller()->IsMaximizeModeWindowManagerEnabled() &&
       session_state_delegate->IsActiveUserSessionStarted() &&
       !session_state_delegate->IsScreenLocked() &&
       session_state_delegate->GetSessionState() ==
           SessionStateDelegate::SESSION_STATE_ACTIVE &&
       shell->system_tray_delegate()->GetUserLoginStatus() !=
           user::LOGGED_IN_KIOSK_APP);
 }
 
 }  // namespace ash