Remove SigninDelegateObserver.

ui/app_list/signin_delegate.h

Index: ui/app_list/signin_delegate.h
diff --git a/ui/app_list/signin_delegate.h b/ui/app_list/signin_delegate.h
index eda67f410e8dea7a182890c8b000356f4c7d36ca..54f59179de961439e43a271ba6491c5ce39601e7 100644
--- a/ui/app_list/signin_delegate.h
+++ b/ui/app_list/signin_delegate.h
@@ -6,14 +6,11 @@
 #define UI_APP_LIST_SIGNIN_DELEGATE_H_
 
 #include "base/basictypes.h"
-#include "base/observer_list.h"
 #include "base/strings/string16.h"
 #include "ui/app_list/app_list_export.h"
 
 namespace app_list {
 
-class SigninDelegateObserver;
-
 class APP_LIST_EXPORT SigninDelegate {
  public:
   SigninDelegate();
@@ -30,15 +27,7 @@ class APP_LIST_EXPORT SigninDelegate {
   virtual base::string16 GetLearnMoreLinkText() = 0;
   virtual base::string16 GetSettingsLinkText() = 0;
 
-  void AddObserver(SigninDelegateObserver* observer);
-  void RemoveObserver(SigninDelegateObserver* observer);
-
- protected:
-  void NotifySigninSuccess();
-
  private:
-  ObserverList<SigninDelegateObserver, true> observers_;
-
   DISALLOW_COPY_AND_ASSIGN(SigninDelegate);
 };