New avatar button: Update when the supervised user ID changes.

chrome/browser/ui/cocoa/profiles/avatar_base_controller.mm

Index: chrome/browser/ui/cocoa/profiles/avatar_base_controller.mm
diff --git a/chrome/browser/ui/cocoa/profiles/avatar_base_controller.mm b/chrome/browser/ui/cocoa/profiles/avatar_base_controller.mm
index 33e969aa57a9261b7d972f59ef9d7ad13804afb0..72eccf4756a789ca2c71db04c996b3b99525c0f1 100644
--- a/chrome/browser/ui/cocoa/profiles/avatar_base_controller.mm
+++ b/chrome/browser/ui/cocoa/profiles/avatar_base_controller.mm
@@ -91,6 +91,11 @@ class ProfileInfoUpdateObserver : public ProfileInfoCacheObserver,
     [avatarController_ updateAvatarButtonAndLayoutParent:YES];
   }
 
+  virtual void OnProfileSupervisedUserIdChanged(
+      const base::FilePath& profile_path) OVERRIDE {
+    [avatarController_ updateAvatarButtonAndLayoutParent:YES];
+  }
+
   // SigninErrorController::Observer:
   virtual void OnErrorChanged() OVERRIDE {
     SigninErrorController* errorController =