chromeos: Replace user image notifications with observer

chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc

Index: chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
diff --git a/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc b/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
index 57b3650bc031f104c953f0bad8dfd6fcda219d1e..8cae860252a764940eee9eb7ee48a5f7c7a0997b 100644
--- a/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
+++ b/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
@@ -528,24 +528,6 @@ bool FakeChromeUserManager::IsUserNonCryptohomeDataEphemeral(
   return false;
 }
 
-void FakeChromeUserManager::AddObserver(UserManager::Observer* obs) {
-  NOTREACHED();
-}
-
-void FakeChromeUserManager::RemoveObserver(UserManager::Observer* obs) {
-  NOTREACHED();
-}
-
-void FakeChromeUserManager::AddSessionStateObserver(
-    UserManager::UserSessionStateObserver* obs) {}
-
-void FakeChromeUserManager::RemoveSessionStateObserver(
-    UserManager::UserSessionStateObserver* obs) {}
-
-void FakeChromeUserManager::NotifyLocalStateChanged() {
-  NOTREACHED();
-}
-
 void FakeChromeUserManager::ChangeUserChildStatus(user_manager::User* user,
                                                   bool is_child) {
   NOTREACHED();