Changing policy while Chrome is running should refresh preferences without relaunching

chrome/browser/configuration_policy_provider_win.cc

 // Copyright (c) 2010 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/configuration_policy_provider_win.h"
 
+#include <userenv.h>
+
 #include <algorithm>
 
 #include "base/logging.h"
+#include "base/object_watcher.h"
 #include "base/registry.h"
 #include "base/scoped_ptr.h"
 #include "base/string_piece.h"
 #include "base/sys_string_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
+#include "base/waitable_event.h"
 #include "chrome/common/policy_constants.h"
 
+ConfigurationPolicyProviderWin::GroupPolicyChangeWatcher::
+    GroupPolicyChangeWatcher(ConfigurationPolicyProvider* provider)
+        : provider_(provider),
+          user_policy_changed_event_(false, false),
+          machine_policy_changed_event_(false, false) {
+  CHECK(RegisterGPNotification(user_policy_changed_event_.handle(), false));
+  CHECK(RegisterGPNotification(machine_policy_changed_event_.handle(), true));
+  user_policy_watcher_.StartWatching(
+      user_policy_changed_event_.handle(),
+      this);
+  machine_policy_watcher_.StartWatching(
+      machine_policy_changed_event_.handle(),
+      this);
+}
+
+void ConfigurationPolicyProviderWin::GroupPolicyChangeWatcher::
+    OnObjectSignaled(HANDLE object) {
+  provider_->NotifyStoreOfPolicyChange();
+  if (object == user_policy_changed_event_.handle()) {
+    user_policy_watcher_.StartWatching(
+        user_policy_changed_event_.handle(),
+        this);
+  } else if (object == machine_policy_changed_event_.handle()) {
+    machine_policy_watcher_.StartWatching(
+        machine_policy_changed_event_.handle(),
+        this);
+  } else {
+    // This method should only be called as a result of signals
+    // to the user- and machine-policy handle watchers.
+    NOTREACHED();
+  }
+}
+
 ConfigurationPolicyProviderWin::ConfigurationPolicyProviderWin() {
+  watcher_.reset(new GroupPolicyChangeWatcher(this));
 }
 
 bool ConfigurationPolicyProviderWin::GetRegistryPolicyString(
     const wchar_t* value_name, string16* result) {
   DWORD value_size = 0;
   DWORD key_type = 0;
   scoped_array<uint8> buffer;
   RegKey hkcu_policy_key(HKEY_LOCAL_MACHINE, policy::kRegistrySubKey);
   if (hkcu_policy_key.ReadValue(value_name, 0, &value_size, &key_type)) {
     if (key_type != REG_SZ)
@@ skipping 91 matching lines @@
         }
         break;
       default:
         NOTREACHED();
         return false;
     }
   }
 
   return true;
 }