Override SigninManager::SignOut if force-signin is enabled.

chrome/browser/signin/force_signin_manager.cc

+// Copyright 2016 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/signin/force_signin_manager.h"
+
+#include "base/bind.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_attributes_entry.h"
+#include "chrome/browser/profiles/profile_attributes_storage.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/user_manager.h"
+#include "chrome/common/pref_names.h"
+#include "components/prefs/pref_service.h"
+
+namespace {
+
+void LockProfile(const base::FilePath& profile_path) {
+  ProfileAttributesEntry* entry;
+  bool has_entry = g_browser_process->profile_manager()
+                       ->GetProfileAttributesStorage()
+                       .GetProfileAttributesWithPath(profile_path, &entry);
+  DCHECK(has_entry);
+  entry->SetIsSigninRequired(true);
+}
+
+void PostPostCloseBrowsersAborted(const base::FilePath& profile_path) {}
+
+}  // namespace
+
+ForceSigninManager::ForceSigninManager(
+    Profile* profile,
+    SigninClient* client,
+    ProfileOAuth2TokenService* token_service,
+    AccountTrackerService* account_tracker_service,
+    GaiaCookieManagerService* cookie_manager_service)
+    : SigninManager(client,
+                    token_service,
+                    account_tracker_service,
+                    cookie_manager_service),
+      profile_(profile) {}
+
+ForceSigninManager::~ForceSigninManager() {}
+
+void ForceSigninManager::SignOut(
+    signin_metrics::ProfileSignout signout_source_metric,
+    signin_metrics::SignoutDelete signout_delete_metric) {
+  if (profile_->IsSystemProfile() || profile_->IsGuestSession()) {
+    SigninManager::SignOut(signout_source_metric, signout_delete_metric);
+  } else {
+    BrowserList::CloseAllBrowsersWithProfile(
+        profile_, base::Bind(&ForceSigninManager::PostCloseBrowsers,
+                             base::Unretained(this), signout_source_metric,
+                             signout_delete_metric),
+        base::Bind(&PostPostCloseBrowsersAborted));
+  }

[Roger Tawa OOO till Jul 10th, 2016/10/26 18:25:31]

I wonder if it is better to always call
BrowserList::CloseAllBrowsersWithProfile() here, and add the check for
system/guest profile inside DoSignOut() ?

+}
+
+// static
+bool ForceSigninManager::IsForceSigninEnabled() {
+  PrefService* prefs = g_browser_process->local_state();
+  return prefs && prefs->GetBoolean(prefs::kForceBrowserSignin);
+}
+
+// static
+void ForceSigninManager::DisableUserManagerDisplayForNextSignOut(
+    SigninManager* signin_manager) {
+  if (IsForceSigninEnabled()) {
+    static_cast<ForceSigninManager*>(signin_manager)
+        ->SetIsUserManagerDisplayed(false);
+  }

[Roger Tawa OOO till Jul 10th, 2016/10/26 18:25:31]

This static cast seems dangerous.  How are we guaranteed that |signin_manager|
is always an instance of ForceSigninManager?  For example, what if the pref
value is changed after the profile is created?

+}
+
+void ForceSigninManager::DoSignOut(
+    signin_metrics::ProfileSignout signout_source_metric,
+    signin_metrics::SignoutDelete signout_delete_metric,
+    const base::FilePath& profile_path) {
+  SigninManager::SignOut(signout_source_metric, signout_delete_metric);
+  LockProfile(profile_path);
+}
+
+void ForceSigninManager::ShowUserManager(const base::FilePath& profile_path) {
+  UserManager::Show(profile_path, profiles::USER_MANAGER_NO_TUTORIAL,
+                    profiles::USER_MANAGER_SELECT_PROFILE_NO_ACTION);
+}
+
+void ForceSigninManager::PostCloseBrowsers(
+    signin_metrics::ProfileSignout signout_source_metric,
+    signin_metrics::SignoutDelete signout_delete_metric,
+    const base::FilePath& profile_path) {
+  DoSignOut(signout_source_metric, signout_delete_metric, profile_path);
+  if (is_user_manager_displayed) {
+    ShowUserManager(profile_path);
+  } else {
+    is_user_manager_displayed = true;
+  }
+}
+
+void ForceSigninManager::SetIsUserManagerDisplayed(bool displayed) {
+  is_user_manager_displayed = displayed;
+}