Disable wifi scans on the VPN tray detailed view

ash/system/chromeos/network/network_state_list_detailed_view.h

Index: ash/system/chromeos/network/network_state_list_detailed_view.h
diff --git a/ash/system/chromeos/network/network_state_list_detailed_view.h b/ash/system/chromeos/network/network_state_list_detailed_view.h
index 9a2b1939b2a2b1b1a7ea787ab919daf3a8377670..297b1aace6c0fb0b68cd23a6c5c8460b81e39b0b 100644
--- a/ash/system/chromeos/network/network_state_list_detailed_view.h
+++ b/ash/system/chromeos/network/network_state_list_detailed_view.h
@@ -57,9 +57,6 @@ class NetworkStateListDetailedView
   DetailedViewType GetViewType() const override;
   void Update() override;
 
-  // Called by the WiFi Scanning Throbber when pressed.
-  bool ThrobberPressed(views::View* sender, const ui::Event& event);
-
  protected:
   // Overridden from ButtonListener.
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;