Change web notifications to show at the top of the list, clean up layout.

ash/system/tray/system_tray.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/system_tray.h"
 
 #include "ash/shell.h"
 #include "ash/shell/panel_window.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/audio/tray_volume.h"
@@ skipping 484 matching lines @@
   if (arrow_offset >= 0)
     init_params.arrow_offset = arrow_offset;
   notification_bubble_->InitView(init_params);
   if (hide_notifications_)
     notification_bubble_->SetVisible(false);
 }
 
 void SystemTray::UpdateNotificationAnchor() {
   if (!notification_bubble_.get())
     return;
-  notification_bubble_->bubble_view()->UpdateAnchor();
+  notification_bubble_->bubble_view()->UpdateBubble();
   // Ensure that the notification buble is above the launcher/status area.
   notification_bubble_->bubble_view()->GetWidget()->StackAtTop();
 }
 
 void SystemTray::SetBorder() {
   // Change the border padding for different shelf alignment.
   if (shelf_alignment() == SHELF_ALIGNMENT_BOTTOM) {
     set_border(views::Border::CreateEmptyBorder(0, 0,
         kPaddingFromBottomOfScreenBottomAlignment,
         kPaddingFromRightEdgeOfScreenBottomAlignment));
@@ skipping 10 matching lines @@
   }
 }
 
 void SystemTray::SetShelfAlignment(ShelfAlignment alignment) {
   if (alignment == shelf_alignment())
     return;
   internal::TrayBackgroundView::SetShelfAlignment(alignment);
   UpdateAfterShelfAlignmentChange(alignment);
   SetBorder();
   tray_container_->UpdateLayout(alignment);
+  // Destroy an existing bubble so that it is rebuilt correctly.
+  bubble_.reset();
+  // Rebuild any notification bubble.
+  if (notification_bubble_.get()) {
+    notification_bubble_.reset();
+    UpdateNotificationBubble();
+  }
 }
 
 bool SystemTray::PerformAction(const views::Event& event) {
   // If we're already showing the default view, hide it; otherwise, show it
   // (and hide any popup that's currently shown).
   if (bubble_.get() &&
       bubble_->bubble_type() == SystemTrayBubble::BUBBLE_TYPE_DEFAULT) {
     bubble_->Close();
   } else {
     int arrow_offset = -1;
@@ skipping 35 matching lines @@
 
 void SystemTray::OnPaintFocusBorder(gfx::Canvas* canvas) {
   // The tray itself expands to the right and bottom edge of the screen to make
   // sure clicking on the edges brings up the popup. However, the focus border
   // should be only around the container.
   if (GetWidget() && GetWidget()->IsActive())
     DrawBorder(canvas, GetContentsBounds());
 }
 
 }  // namespace ash