chromeos: Replace user image notifications with observer

chrome/browser/ui/webui/options/browser_options_handler.h

Index: chrome/browser/ui/webui/options/browser_options_handler.h
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.h b/chrome/browser/ui/webui/options/browser_options_handler.h
index f9f03a9e379938ee79df553a350a0324ca3b2928..b8872997781f2e0816fca42581ce0f12a28c22d4 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.h
+++ b/chrome/browser/ui/webui/options/browser_options_handler.h
@@ -37,6 +37,7 @@
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/system/pointer_device_observer.h"
 #include "chrome/browser/ui/app_list/arc/arc_app_list_prefs.h"
+#include "components/user_manager/user_manager.h"
 #else  // defined(OS_CHROMEOS)
 #include "chrome/browser/shell_integration.h"
 #endif  // !defined(OS_CHROMEOS)
@@ -63,6 +64,7 @@ class BrowserOptionsHandler
 #if defined(OS_CHROMEOS)
       public chromeos::system::PointerDeviceObserver::Observer,
       public ArcAppListPrefs::Observer,
+      public user_manager::UserManager::Observer,
 #endif
       public TemplateURLServiceObserver,
       public extensions::ExtensionRegistryObserver,
@@ -149,6 +151,9 @@ class BrowserOptionsHandler
   void OnAppRemoved(const std::string& app_id) override;
   void OnAppRegistered(const std::string& app_id,
                        const ArcAppListPrefs::AppInfo& app_info) override;
+
+  // user_manager::UserManager::Observer overrides.
+  void OnUserImageChanged(const user_manager::User& user) override;
 #endif
 
   void UpdateSyncState();