Always tear down the OSX app list signin view, when the signin status changes.

ui/app_list/cocoa/app_list_view_controller.mm

 // Copyright 2013 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.
 
 #import "ui/app_list/cocoa/app_list_view_controller.h"
 
 #include "base/mac/foundation_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "skia/ext/skia_utils_mac.h"
@@ skipping 321 matching lines @@
 - (void)redoSearch {
   [self modelTextDidChange];
 }
 
 - (void)onSigninStatusChanged {
   [appsSearchBoxController_ rebuildMenu];
   app_list::SigninDelegate* signinDelegate =
       delegate_ ? delegate_->GetSigninDelegate() : NULL;
   BOOL show_signin_view =
       signinDelegate && ![appsGridController_ model]->signed_in();
-  if (!!signinViewController_ == show_signin_view)
-    return;
+
+  [[signinViewController_ view] removeFromSuperview];
+  signinViewController_.reset();
 
   if (!show_signin_view) {
-    [[signinViewController_ view] removeFromSuperview];
-    signinViewController_.reset();
     [backgroundView_ setHidden:NO];
     return;
   }
 
   [backgroundView_ setHidden:YES];
   signinViewController_.reset(
       [[SigninViewController alloc] initWithFrame:[backgroundView_ frame]
                                      cornerRadius:kBubbleCornerRadius
                                          delegate:signinDelegate]);
   [[self view] addSubview:[signinViewController_ view]];
 }
 
 @end