Revert of chromeos: Move ownership of system tray width from chrome to ash

ash/common/system/tray/default_system_tray_delegate.cc

 // Copyright 2013 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/common/system/tray/default_system_tray_delegate.h"
 
 #include <string>
 #include <utility>
 
 #include "ash/common/system/networking_config_delegate.h"
@@ skipping 45 matching lines @@
 }
 
 bool DefaultSystemTrayDelegate::GetBluetoothEnabled() {
   return bluetooth_enabled_;
 }
 
 bool DefaultSystemTrayDelegate::GetBluetoothDiscovering() {
   return false;
 }
 
+int DefaultSystemTrayDelegate::GetSystemTrayMenuWidth() {
+  // This is the default width for English languages.
+  return 300;
+}
+
 }  // namespace ash