mash: Create system tray display and rotation lock items via delegate

ash/common/system/tray/system_tray_delegate.h

 // 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.
 
 #ifndef ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 #define ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 11 matching lines @@
 
 namespace base {
 class TimeDelta;
 class TimeTicks;
 }
 
 namespace ash {
 
 class CustodianInfoTrayObserver;
 class ShutdownPolicyObserver;
+class SystemTray;
+class SystemTrayItem;
 
 struct ASH_EXPORT NetworkIconInfo {
   NetworkIconInfo();
   ~NetworkIconInfo();
 
   bool highlight() const { return connected || connecting; }
 
   bool connecting;
   bool connected;
   bool tray_icon_visible;
@@ skipping 134 matching lines @@
   // Shows the settings related to date, timezone etc.
   virtual void ShowDateSettings();
 
   // Shows the dialog to set system time, date, and timezone.
   virtual void ShowSetTimeDialog();
 
   // Shows the settings related to network. If |guid| is not empty,
   // show the settings for the corresponding network.
   virtual void ShowNetworkSettingsForGuid(const std::string& guid);
 
+  // Creates the system tray item for display settings.

[msw, 2016/07/13 18:51:49]

nit: Move far down (not amid Show* functions). Despite a minor relation to
ShowDisplaySettings(), it's rather distinct and a short-term measure that should
be removed later (right?). Maybe add a comment about the long-term plan here?

[James Cook, 2016/07/13 21:30:46]

Done.

+  virtual std::unique_ptr<SystemTrayItem> CreateDisplayTrayItem(
+      SystemTray* tray);
+
   // Shows settings related to multiple displays.
   virtual void ShowDisplaySettings();
 
   // Shows settings related to power.
   virtual void ShowPowerSettings();
 
   // Shows the page that lets you disable performance tracing.
   virtual void ShowChromeSlow();
 
   // Returns true if the notification for the display configuration change
@@ skipping 137 matching lines @@
   // asynchronously calls |callback| once a trusted policy becomes available.
   virtual void ShouldRebootOnShutdown(const RebootOnShutdownCallback& callback);
 
   // Returns VPNDelegate. May return nullptr.
   virtual VPNDelegate* GetVPNDelegate() const;
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_