Fix sketchy User Manager code :(

chrome/browser/ui/webui/signin/user_manager_screen_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/signin/user_manager_screen_handler.h"
 
 #include "base/bind.h"
 #include "base/value_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 62 matching lines @@
   if (status != Profile::CREATE_STATUS_INITIALIZED)
     return;
   profiles::FindOrCreateNewWindowForProfile(
     profile,
     chrome::startup::IS_PROCESS_STARTUP,
     chrome::startup::IS_FIRST_RUN,
     desktop_type,
     false);
 }
 
+// This callback is run after switching to a new profile has finished. This
+// means either a new browser window has been opened, or an existing one
+// has been found, which means we can safely close the User Manager without
+// accidentally terminating the browser process.
+void OnSwitchToProfileComplete() {
+  base::MessageLoop::current()->PostTask(

[Alexei Svitkine (slow), 2014/02/06 22:02:12]

Your comment should explain why this is posted rather than executed directly.

[noms (inactive), 2014/02/06 22:51:34]

Done.

+        FROM_HERE,
+        base::Bind(&chrome::HideUserManager));
+}
+
 std::string GetAvatarImageAtIndex(
     size_t index, const ProfileInfoCache& info_cache) {
   bool is_gaia_picture =
       info_cache.IsUsingGAIAPictureOfProfileAtIndex(index) &&
       info_cache.GetGAIAPictureOfProfileAtIndex(index);
 
   gfx::Image icon = profiles::GetSizedAvatarIconWithBorder(
       info_cache.GetAvatarIconOfProfileAtIndex(index),
       is_gaia_picture, kAvatarIconSize, kAvatarIconSize);
   return webui::GetBitmapDataUrl(icon.AsBitmap());
@@ skipping 85 matching lines @@
 
 void UserManagerScreenHandler::HandleInitialize(const base::ListValue* args) {
   SendUserList();
   web_ui()->CallJavascriptFunction("cr.ui.Oobe.showUserManagerScreen");
   desktop_type_ = chrome::GetHostDesktopTypeForNativeView(
       web_ui()->GetWebContents()->GetView()->GetNativeView());
 }
 
 void UserManagerScreenHandler::HandleAddUser(const base::ListValue* args) {
   profiles::CreateAndSwitchToNewProfile(desktop_type_,
-                                        base::Bind(&chrome::HideUserManager),
+                                        base::Bind(&OnSwitchToProfileComplete),
                                         ProfileMetrics::ADD_NEW_USER_MANAGER);
 }
 
 void UserManagerScreenHandler::HandleAuthenticatedLaunchUser(
     const base::ListValue* args) {
   base::string16 email_address;
   if (!args->GetString(0, &email_address))
     return;
 
   base::string16 display_name;
@@ skipping 57 matching lines @@
     return;
 
   g_browser_process->profile_manager()->ScheduleProfileForDeletion(
       profile_path,
       base::Bind(&OpenNewWindowForProfile, desktop_type_));
   ProfileMetrics::LogProfileDeleteUser(ProfileMetrics::PROFILE_DELETED);
 }
 
 void UserManagerScreenHandler::HandleLaunchGuest(const base::ListValue* args) {
   profiles::SwitchToGuestProfile(desktop_type_,
-                                 base::Bind(&chrome::HideUserManager));
+                                 base::Bind(&OnSwitchToProfileComplete));
   ProfileMetrics::LogProfileSwitchUser(ProfileMetrics::SWITCH_PROFILE_GUEST);
 }
 
 void UserManagerScreenHandler::HandleLaunchUser(const base::ListValue* args) {
   base::string16 email_address;
   base::string16 display_name;
 
   if (!args->GetString(0, &email_address) ||
       !args->GetString(1, &display_name)) {
     NOTREACHED();
@@ skipping 16 matching lines @@
   // we have to validate in (secure) C++ code that it really is a profile
   // not needing authentication.  If it is, just ignore the "launch" request.
   if (info_cache.ProfileIsSigninRequiredAtIndex(profile_index))
     return;
   ProfileMetrics::LogProfileAuthResult(ProfileMetrics::AUTH_UNNECESSARY);
 
   base::FilePath path = info_cache.GetPathOfProfileAtIndex(profile_index);
   profiles::SwitchToProfile(path,
                             desktop_type_,
                             false,  /* reuse any existing windows */
-                            base::Bind(&chrome::HideUserManager),
+                            base::Bind(&OnSwitchToProfileComplete),
                             ProfileMetrics::SWITCH_PROFILE_MANAGER);
 }
 
 void UserManagerScreenHandler::OnClientLoginSuccess(
     const ClientLoginResult& result) {
   chrome::SetLocalAuthCredentials(authenticating_profile_index_,
                                   password_attempt_);
   ReportAuthenticationResult(true, ProfileMetrics::AUTH_ONLINE);
 }
 
@@ skipping 151 matching lines @@
   password_attempt_.clear();
 
   if (success) {
     ProfileInfoCache& info_cache =
         g_browser_process->profile_manager()->GetProfileInfoCache();
     info_cache.SetProfileSigninRequiredAtIndex(
         authenticating_profile_index_, false);
     base::FilePath path = info_cache.GetPathOfProfileAtIndex(
         authenticating_profile_index_);
     profiles::SwitchToProfile(path, desktop_type_, true,
-                              base::Bind(&chrome::HideUserManager),
+                              base::Bind(&OnSwitchToProfileComplete),
                               ProfileMetrics::SWITCH_PROFILE_UNLOCK);
   } else {
     web_ui()->CallJavascriptFunction(
         "cr.ui.Oobe.showSignInError",
         base::FundamentalValue(0),
         base::StringValue(
             l10n_util::GetStringUTF8(IDS_LOGIN_ERROR_AUTHENTICATING)),
         base::StringValue(""),
         base::FundamentalValue(0));
   }
 }