Disable guest mode by default if force sign in is enabled.

chrome/browser/profiles/guest_mode_policy_handler.cc

Index: chrome/browser/profiles/guest_mode_policy_handler.cc
diff --git a/chrome/browser/profiles/guest_mode_policy_handler.cc b/chrome/browser/profiles/guest_mode_policy_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..151cf07cb6a837e3bb47895b661af9bbdd54469a
--- /dev/null
+++ b/chrome/browser/profiles/guest_mode_policy_handler.cc
@@ -0,0 +1,41 @@
+// 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/profiles/guest_mode_policy_handler.h"
+
+#include "base/values.h"
+#include "chrome/common/pref_names.h"
+#include "components/policy/core/common/policy_map.h"
+#include "components/policy/policy_constants.h"
+#include "components/prefs/pref_value_map.h"
+
+namespace policy {
+
+GuestModePolicyHandler::GuestModePolicyHandler()
+    : TypeCheckingPolicyHandler(key::kBrowserGuestModeEnabled,
+                                base::Value::TYPE_BOOLEAN) {}
+
+GuestModePolicyHandler::~GuestModePolicyHandler() {}
+
+void GuestModePolicyHandler::ApplyPolicySettings(const PolicyMap& policies,
+                                                 PrefValueMap* prefs) {
+  const base::Value* guest_mode_value = policies.GetValue(policy_name());
+  bool is_guest_mode_enabled;
+  if (guest_mode_value &&
+      guest_mode_value->GetAsBoolean(&is_guest_mode_enabled)) {
+    prefs->SetBoolean(prefs::kBrowserGuestModeEnabled, is_guest_mode_enabled);
+    return;
+  }
+  // Disable guest mode by default if force signin is enabled.
+  const base::Value* force_signin_value =
+      policies.GetValue(key::kForceBrowserSignin);
+  bool is_force_signin_enabled;
+  if (force_signin_value &&
+      force_signin_value->GetAsBoolean(&is_force_signin_enabled) &&
+      is_force_signin_enabled) {
+    prefs->SetBoolean(prefs::kBrowserGuestModeEnabled, false);
+  }
+}
+
+}  // namespace policy