Clean up some ash constants.

ash/system/web_notification/ash_popup_alignment_delegate.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/web_notification/ash_popup_alignment_delegate.h"
 
 #include "ash/public/cpp/shelf_types.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_constants.h"
@@ skipping 44 matching lines @@
     UpdateWorkArea();
 }
 
 void AshPopupAlignmentDelegate::SetTrayBubbleHeight(int height) {
   tray_bubble_height_ = height;
 
   // If the shelf is shown during auto-hide state, the distance from the edge
   // should be reduced by the height of shelf's shown height.
   if (shelf_->GetVisibilityState() == SHELF_AUTO_HIDE &&
       shelf_->GetAutoHideState() == SHELF_AUTO_HIDE_SHOWN) {
-    tray_bubble_height_ -= GetShelfConstant(SHELF_SIZE) -
-                           GetShelfConstant(SHELF_INSETS_FOR_AUTO_HIDE);
+    tray_bubble_height_ -= kShelfSize;
   }
 
   if (tray_bubble_height_ > 0)
     tray_bubble_height_ += message_center::kMarginBetweenItems;
   else
     tray_bubble_height_ = 0;
 
   DoUpdateIfPossible();
 }
 
@@ skipping 82 matching lines @@
     const display::Display& old_display) {}
 
 void AshPopupAlignmentDelegate::OnDisplayMetricsChanged(
     const display::Display& display,
     uint32_t metrics) {
   if (GetCurrentDisplay().id() == display.id())
     UpdateWorkArea();
 }
 
 }  // namespace ash