Revert of ash: Use system tray mojo interface to show system update tray icon

chrome/browser/ui/ash/system_tray_client.h

Index: chrome/browser/ui/ash/system_tray_client.h
diff --git a/chrome/browser/ui/ash/system_tray_client.h b/chrome/browser/ui/ash/system_tray_client.h
index 6ea72c3bea50b34f92569d54f753e6a9080a799b..82e82dfd410eae6f4b9bdd6e56bc534872d37bdd 100644
--- a/chrome/browser/ui/ash/system_tray_client.h
+++ b/chrome/browser/ui/ash/system_tray_client.h
@@ -8,8 +8,6 @@
 #include "ash/public/interfaces/system_tray.mojom.h"
 #include "base/macros.h"
 #include "chrome/browser/chromeos/system/system_clock_observer.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 namespace ash {
@@ -25,8 +23,7 @@
 // relevant state changes in chrome.
 // TODO: Consider renaming this to SystemTrayClientChromeOS.
 class SystemTrayClient : public ash::mojom::SystemTrayClient,
-                         public chromeos::system::SystemClockObserver,
-                         public content::NotificationObserver {
+                         public chromeos::system::SystemClockObserver {
  public:
   SystemTrayClient();
   ~SystemTrayClient() override;
@@ -45,10 +42,6 @@
   // The returned widget is owned by its native widget.
   static views::Widget* CreateUnownedDialogWidget(
       views::WidgetDelegate* widget_delegate);
-
-  // Shows an update icon for an Adobe Flash update and forces a device reboot
-  // when the update is applied.
-  void SetFlashUpdateAvailable();
 
   // ash::mojom::SystemTrayClient:
   void ShowSettings() override;
@@ -73,16 +66,8 @@
   void RequestRestartForUpdate() override;
 
  private:
-  // Requests that ash show the update available icon.
-  void HandleUpdateAvailable();
-
   // chromeos::system::SystemClockObserver:
   void OnSystemClockChanged(chromeos::system::SystemClock* clock) override;
-
-  // content::NotificationObserver:
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
 
   // System tray mojo service in ash.
   ash::mojom::SystemTrayPtr system_tray_;
@@ -90,11 +75,6 @@
   // Binds this object to the client interface.
   mojo::Binding<ash::mojom::SystemTrayClient> binding_;
 
-  // Whether an Adobe Flash component update is available.
-  bool flash_update_available_ = false;
-
-  content::NotificationRegistrar registrar_;
-
   DISALLOW_COPY_AND_ASSIGN(SystemTrayClient);
 };