Clean up some ash constants.

ash/system/web_notification/ash_popup_alignment_delegate.cc

Index: ash/system/web_notification/ash_popup_alignment_delegate.cc
diff --git a/ash/system/web_notification/ash_popup_alignment_delegate.cc b/ash/system/web_notification/ash_popup_alignment_delegate.cc
index 41fa4f7af0b660ed8288c25083e1b45ba477eb07..360062a087854595b8a2c9ed12dca3fad9da3e9b 100644
--- a/ash/system/web_notification/ash_popup_alignment_delegate.cc
+++ b/ash/system/web_notification/ash_popup_alignment_delegate.cc
@@ -62,8 +62,7 @@ void AshPopupAlignmentDelegate::SetTrayBubbleHeight(int height) {
   // 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)