Create AvatarMenuModel for the new avatar menu interface.

chrome/browser/profiles/avatar_menu_model_observer.h

Index: chrome/browser/profiles/avatar_menu_model_observer.h
diff --git a/chrome/browser/profiles/avatar_menu_model_observer.h b/chrome/browser/profiles/avatar_menu_model_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..06436224455bf90a595313240e2712ca82a937a4
--- /dev/null
+++ b/chrome/browser/profiles/avatar_menu_model_observer.h
@@ -0,0 +1,17 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_PROFILES_AVATAR_MENU_MODEL_OBSERVER_H_
+#define CHROME_BROWSER_PROFILES_AVATAR_MENU_MODEL_OBSERVER_H_
+
+// Delegate interface for objects that want to be notified when the
+// AvatarMenuModel changes.
+class AvatarMenuModelObserver {
+ public:
+  virtual ~AvatarMenuModelObserver() {}
+
+  virtual void OnAvatarMenuModelChanged() = 0;
+};
+
+#endif  // CHROME_BROWSER_PROFILES_AVATAR_MENU_MODEL_OBSERVER_H_