Add WebNotificationTray

ash/wm/shelf_layout_manager.cc

Index: ash/wm/shelf_layout_manager.cc
diff --git a/ash/wm/shelf_layout_manager.cc b/ash/wm/shelf_layout_manager.cc
index e986853d7121827e5a1023d408a3e45860d6c1dc..6ee4281c1500ca63a462e1e0e261d32aa3f36c2a 100644
--- a/ash/wm/shelf_layout_manager.cc
+++ b/ash/wm/shelf_layout_manager.cc
@@ -13,6 +13,7 @@
 #include "ash/shell_window_ids.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/system_tray.h"
+#include "ash/system/web_notification/web_notification_tray.h"
 #include "ash/wm/workspace/workspace_manager.h"
 #include "base/auto_reset.h"
 #include "base/i18n/rtl.h"
@@ -200,6 +201,8 @@ bool ShelfLayoutManager::SetAlignment(ShelfAlignment alignment) {
     Shell::GetInstance()->status_area_widget()->SetShelfAlignment(alignment);
   if (Shell::GetInstance()->system_tray())
     Shell::GetInstance()->system_tray()->SetShelfAlignment(alignment);
+  if (Shell::GetInstance()->web_notification_tray())
+    Shell::GetInstance()->web_notification_tray()->SetShelfAlignment(alignment);
   LayoutShelf();
   return true;
 }
@@ -499,6 +502,10 @@ void ShelfLayoutManager::UpdateShelfBackground(
     Shell::GetInstance()->system_tray()->SetPaintsBackground(
         !launcher_paints, type);
   }
+  if (Shell::GetInstance()->web_notification_tray()) {
+    Shell::GetInstance()->web_notification_tray()->SetPaintsBackground(
+        !launcher_paints, type);
+  }
 }
 
 bool ShelfLayoutManager::GetLauncherPaintsBackground() const {