chromeos: Refactor system tray ShowNetworkSettingsForGuid for mash

ash/common/system/tray/system_tray_delegate.h

Index: ash/common/system/tray/system_tray_delegate.h
diff --git a/ash/common/system/tray/system_tray_delegate.h b/ash/common/system/tray/system_tray_delegate.h
index 9751f556c87aad3189b0608e4871c6068633213f..c41a839b7b558b7b5c03c8cb83d7da8210c572ae 100644
--- a/ash/common/system/tray/system_tray_delegate.h
+++ b/ash/common/system/tray/system_tray_delegate.h
@@ -150,10 +150,6 @@ class ASH_EXPORT SystemTrayDelegate {
   // 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);
-
   // Returns true if the notification for the display configuration change
   // should appear.
   virtual bool ShouldShowDisplayNotification();