Respect NAT traversal policy in the Me2Me host.

Now the Me2Me host uses the same policy value that It2Me checks to determine if NAT traversal should be enabled. policy_hack has been moved to remoting/host because now it is used not only by the plugin. Also fixed a bug in the policy loader that would cause 5 seconds delay when starting (affects It2Me too).

BUG=114254

Review URL: http://codereview.chromium.org/9401022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@122195 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 719 insertions, 0 deletions

diff --git a/remoting/host/policy_hack/nat_policy.cc b/remoting/host/policy_hack/nat_policy.cc
new file mode 100644
index 0000000..631550b
--- /dev/null
+++ b/remoting/host/policy_hack/nat_policy.cc
@@ -0,0 +1,112 @@
+// Copyright (c) 2012 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.
+
+// Most of this code is copied from:
+//   src/chrome/browser/policy/asynchronous_policy_loader.{h,cc}
+
+#include "remoting/host/policy_hack/nat_policy.h"
+
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/location.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop_proxy.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/time.h"
+#include "base/values.h"
+
+namespace remoting {
+namespace policy_hack {
+
+namespace {
+// The time interval for rechecking policy. This is our fallback in case the
+// delegate never reports a change to the ReloadObserver.
+const int kFallbackReloadDelayMinutes = 15;
+
+}  // namespace
+
+const char NatPolicy::kNatPolicyName[] = "RemoteAccessHostFirewallTraversal";
+
+NatPolicy::NatPolicy(base::MessageLoopProxy* message_loop_proxy)
+    : message_loop_proxy_(message_loop_proxy),
+      current_nat_enabled_state_(false),
+      first_state_published_(false),
+      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {
+}
+
+NatPolicy::~NatPolicy() {
+}
+
+void NatPolicy::StartWatching(const NatEnabledCallback& nat_enabled_cb) {
+  if (!OnPolicyThread()) {
+    message_loop_proxy_->PostTask(FROM_HERE,
+                                  base::Bind(&NatPolicy::StartWatching,
+                                             base::Unretained(this),
+                                             nat_enabled_cb));
+    return;
+  }
+
+  nat_enabled_cb_ = nat_enabled_cb;
+  StartWatchingInternal();
+}
+
+void NatPolicy::StopWatching(base::WaitableEvent* done) {
+  if (!OnPolicyThread()) {
+    message_loop_proxy_->PostTask(FROM_HERE,
+                                  base::Bind(&NatPolicy::StopWatching,
+                                             base::Unretained(this), done));
+    return;
+  }
+
+  StopWatchingInternal();
+  weak_factory_.InvalidateWeakPtrs();
+  nat_enabled_cb_.Reset();
+
+  done->Signal();
+}
+
+void NatPolicy::ScheduleFallbackReloadTask() {
+  DCHECK(OnPolicyThread());
+  ScheduleReloadTask(
+      base::TimeDelta::FromMinutes(kFallbackReloadDelayMinutes));
+}
+
+void NatPolicy::ScheduleReloadTask(const base::TimeDelta& delay) {
+  DCHECK(OnPolicyThread());
+  message_loop_proxy_->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&NatPolicy::Reload, weak_factory_.GetWeakPtr()),
+      delay.InMilliseconds());
+}
+
+bool NatPolicy::OnPolicyThread() const {
+  return message_loop_proxy_->BelongsToCurrentThread();
+}
+
+void NatPolicy::UpdateNatPolicy(base::DictionaryValue* new_policy) {
+  DCHECK(OnPolicyThread());
+  bool new_nat_enabled_state = false;
+  if (!new_policy->HasKey(kNatPolicyName)) {
+    // If unspecified, the default value of this policy is true.
+    new_nat_enabled_state = true;
+  } else {
+    // Otherwise, try to parse the value and only change from false if we get
+    // a successful read.
+    base::Value* value;
+    if (new_policy->Get(kNatPolicyName, &value) &&
+        value->IsType(base::Value::TYPE_BOOLEAN)) {
+      CHECK(value->GetAsBoolean(&new_nat_enabled_state));
+    }
+  }
+
+  if (!first_state_published_ ||
+      (new_nat_enabled_state != current_nat_enabled_state_)) {
+    first_state_published_ = true;
+    current_nat_enabled_state_ = new_nat_enabled_state;
+    nat_enabled_cb_.Run(current_nat_enabled_state_);
+  }
+}
+
+}  // namespace policy_hack
+}  // namespace remoting
diff --git a/remoting/host/policy_hack/nat_policy.h b/remoting/host/policy_hack/nat_policy.h
new file mode 100644
index 0000000..4984d1f
--- /dev/null
+++ b/remoting/host/policy_hack/nat_policy.h
@@ -0,0 +1,78 @@
+// Copyright (c) 2012 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.
+
+#ifndef REMOTING_HOST_POLICY_HACK_NAT_POLICY_H_
+#define REMOTING_HOST_POLICY_HACK_NAT_POLICY_H_
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+
+namespace base {
+class DictionaryValue;
+class MessageLoopProxy;
+class TimeDelta;
+class WaitableEvent;
+}  // namespace base
+
+namespace remoting {
+namespace policy_hack {
+
+// Watches for changes to the managed remote access host NAT policies.
+// If StartWatching() has been called, then before this object can be deleted,
+// StopWatching() have completed (the provided |done| event must be signaled).
+class NatPolicy {
+ public:
+  // Called with the current status of whether or not NAT traversal is enabled.
+  typedef base::Callback<void(bool)> NatEnabledCallback;
+
+  explicit NatPolicy(base::MessageLoopProxy* message_loop_proxy);
+  virtual ~NatPolicy();
+
+  // This guarantees that the |nat_enabled_cb| is called at least once with
+  // the current policy.  After that, |nat_enabled_cb| will be called whenever
+  // a change to the nat policy is detected.
+  virtual void StartWatching(const NatEnabledCallback& nat_enabled_cb);
+
+  // Should be called after StartWatching() before the object is deleted. Calls
+  // just wait for |done| to be signaled before deleting the object.
+  virtual void StopWatching(base::WaitableEvent* done);
+
+  // Implemented by each platform.  This message loop should be an IO message
+  // loop.
+  static NatPolicy* Create(base::MessageLoopProxy* message_loop_proxy);
+
+ protected:
+  virtual void StartWatchingInternal() = 0;
+  virtual void StopWatchingInternal() = 0;
+  virtual void Reload() = 0;
+
+  // Used to check if the class is on the right thread.
+  bool OnPolicyThread() const;
+
+  // Takes the policy dictionary from the OS specific store and extracts the
+  // NAT traversal setting.
+  void UpdateNatPolicy(base::DictionaryValue* new_policy);
+
+  // Used for time-based reloads in case something goes wrong with the
+  // notification system.
+  void ScheduleFallbackReloadTask();
+  void ScheduleReloadTask(const base::TimeDelta& delay);
+
+  static const char kNatPolicyName[];
+
+ private:
+  scoped_refptr<base::MessageLoopProxy> message_loop_proxy_;
+
+  NatEnabledCallback nat_enabled_cb_;
+  bool current_nat_enabled_state_;
+  bool first_state_published_;
+
+  // Allows us to cancel any inflight FileWatcher events or scheduled reloads.
+  base::WeakPtrFactory<NatPolicy> weak_factory_;
+};
+
+}  // namespace policy_hack
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_POLICY_HACK_NAT_POLICY_H_
diff --git a/remoting/host/policy_hack/nat_policy_linux.cc b/remoting/host/policy_hack/nat_policy_linux.cc
new file mode 100644
index 0000000..6037ddc
--- /dev/null
+++ b/remoting/host/policy_hack/nat_policy_linux.cc
@@ -0,0 +1,273 @@
+// Copyright (c) 2012 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.
+
+// Most of this code is copied from various classes in
+// src/chrome/browser/policy. In particular, look at
+//
+//   file_based_policy_loader.{h,cc}
+//   config_dir_policy_provider.{h,cc}
+//
+// This is a reduction of the functionality in those classes.
+
+#include <set>
+
+#include "remoting/host/policy_hack/nat_policy.h"
+
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/files/file_path_watcher.h"
+#include "base/json/json_value_serializer.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop_proxy.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/time.h"
+#include "base/values.h"
+
+namespace remoting {
+namespace policy_hack {
+
+namespace {
+
+const FilePath::CharType kPolicyDir[] =
+    FILE_PATH_LITERAL("/etc/opt/chrome/policies/managed");
+
+// Amount of time we wait for the files on disk to settle before trying to load
+// them. This alleviates the problem of reading partially written files and
+// makes it possible to batch quasi-simultaneous changes.
+const int kSettleIntervalSeconds = 5;
+
+}  // namespace
+
+class NatPolicyLinux : public NatPolicy {
+ public:
+  NatPolicyLinux(base::MessageLoopProxy* message_loop_proxy,
+                 const FilePath& config_dir)
+      : NatPolicy(message_loop_proxy),
+        config_dir_(config_dir),
+        ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {
+    // Detach the factory because we ensure that only the policy thread ever
+    // calls methods on this. Also, the API contract of having to call
+    // StopWatching() (which signals completion) after StartWatching()
+    // before this object can be destructed ensures there are no users of
+    // this object before it is destructed.
+    weak_factory_.DetachFromThread();
+  }
+
+  virtual ~NatPolicyLinux() {}
+
+ protected:
+  virtual void StartWatchingInternal() OVERRIDE {
+    DCHECK(OnPolicyThread());
+    watcher_.reset(new base::files::FilePathWatcher());
+
+    if (!config_dir_.empty() &&
+        !watcher_->Watch(
+            config_dir_,
+            new FilePathWatcherDelegate(weak_factory_.GetWeakPtr()))) {
+      OnFilePathError(config_dir_);
+    }
+
+    // There might have been changes to the directory in the time between
+    // construction of the loader and initialization of the watcher. Call reload
+    // to detect if that is the case.
+    Reload();
+
+    ScheduleFallbackReloadTask();
+  }
+
+  virtual void StopWatchingInternal() OVERRIDE {
+    DCHECK(OnPolicyThread());
+    // Cancel any inflight requests.
+    watcher_.reset();
+  }
+
+  // Called by FilePathWatcherDelegate.
+  virtual void OnFilePathError(const FilePath& path) {
+    LOG(ERROR) << "NatPolicyLinux on " << path.value()
+               << " failed.";
+  }
+
+  // Called by FilePathWatcherDelegate.
+  virtual void OnFilePathChanged(const FilePath& path) {
+    DCHECK(OnPolicyThread());
+
+    Reload();
+  }
+
+ private:
+  // Needed to avoid refcounting NatPolicyLinux.
+  class FilePathWatcherDelegate :
+    public base::files::FilePathWatcher::Delegate {
+   public:
+    FilePathWatcherDelegate(base::WeakPtr<NatPolicyLinux> policy_watcher)
+        : policy_watcher_(policy_watcher) {
+    }
+
+    virtual void OnFilePathError(const FilePath& path) {
+      if (policy_watcher_) {
+        policy_watcher_->OnFilePathError(path);
+      }
+    }
+
+    virtual void OnFilePathChanged(const FilePath& path) {
+      if (policy_watcher_) {
+        policy_watcher_->OnFilePathChanged(path);
+      }
+    }
+
+   private:
+    base::WeakPtr<NatPolicyLinux> policy_watcher_;
+  };
+
+  base::Time GetLastModification() {
+    DCHECK(OnPolicyThread());
+    base::Time last_modification = base::Time();
+    base::PlatformFileInfo file_info;
+
+    // If the path does not exist or points to a directory, it's safe to load.
+    if (!file_util::GetFileInfo(config_dir_, &file_info) ||
+        !file_info.is_directory) {
+      return last_modification;
+    }
+
+    // Enumerate the files and find the most recent modification timestamp.
+    file_util::FileEnumerator file_enumerator(config_dir_,
+                                              false,
+                                              file_util::FileEnumerator::FILES);
+    for (FilePath config_file = file_enumerator.Next();
+         !config_file.empty();
+         config_file = file_enumerator.Next()) {
+      if (file_util::GetFileInfo(config_file, &file_info) &&
+          !file_info.is_directory) {
+        last_modification = std::max(last_modification,
+                                     file_info.last_modified);
+      }
+    }
+
+    return last_modification;
+  }
+
+  // Caller owns the value.
+  DictionaryValue* Load() {
+    DCHECK(OnPolicyThread());
+    // Enumerate the files and sort them lexicographically.
+    std::set<FilePath> files;
+    file_util::FileEnumerator file_enumerator(config_dir_, false,
+                                              file_util::FileEnumerator::FILES);
+    for (FilePath config_file_path = file_enumerator.Next();
+         !config_file_path.empty(); config_file_path = file_enumerator.Next())
+      files.insert(config_file_path);
+
+    // Start with an empty dictionary and merge the files' contents.
+    DictionaryValue* policy = new DictionaryValue();
+    for (std::set<FilePath>::iterator config_file_iter = files.begin();
+         config_file_iter != files.end(); ++config_file_iter) {
+      JSONFileValueSerializer deserializer(*config_file_iter);
+      int error_code = 0;
+      std::string error_msg;
+      scoped_ptr<Value> value(
+          deserializer.Deserialize(&error_code, &error_msg));
+      if (!value.get()) {
+        LOG(WARNING) << "Failed to read configuration file "
+                     << config_file_iter->value() << ": " << error_msg;
+        continue;
+      }
+      if (!value->IsType(Value::TYPE_DICTIONARY)) {
+        LOG(WARNING) << "Expected JSON dictionary in configuration file "
+                     << config_file_iter->value();
+        continue;
+      }
+      policy->MergeDictionary(static_cast<DictionaryValue*>(value.get()));
+    }
+
+    return policy;
+  }
+
+  void Reload() {
+    DCHECK(OnPolicyThread());
+    // Check the directory time in order to see whether a reload is required.
+    base::TimeDelta delay;
+    base::Time now = base::Time::Now();
+    if (!IsSafeToReloadPolicy(now, &delay)) {
+      ScheduleReloadTask(delay);
+      return;
+    }
+
+    // Check again in case the directory has changed while reading it.
+    if (!IsSafeToReloadPolicy(now, &delay)) {
+      ScheduleReloadTask(delay);
+      return;
+    }
+
+    // Load the policy definitions.
+    scoped_ptr<DictionaryValue> new_policy(Load());
+    UpdateNatPolicy(new_policy.get());
+
+    ScheduleFallbackReloadTask();
+  }
+
+  bool IsSafeToReloadPolicy(const base::Time& now, base::TimeDelta* delay) {
+    DCHECK(OnPolicyThread());
+    DCHECK(delay);
+    const base::TimeDelta kSettleInterval =
+        base::TimeDelta::FromSeconds(kSettleIntervalSeconds);
+
+    base::Time last_modification = GetLastModification();
+    if (last_modification.is_null())
+      return true;
+
+    if (last_modification_file_.is_null())
+      last_modification_file_ = last_modification;
+
+    // If there was a change since the last recorded modification, wait some
+    // more.
+    if (last_modification != last_modification_file_) {
+      last_modification_file_ = last_modification;
+      last_modification_clock_ = now;
+      *delay = kSettleInterval;
+      return false;
+    }
+
+    // Check whether the settle interval has elapsed.
+    base::TimeDelta age = now - last_modification_clock_;
+    if (age < kSettleInterval) {
+      *delay = kSettleInterval - age;
+      return false;
+    }
+
+    return true;
+  }
+
+  // Managed with a scoped_ptr rather than being declared as an inline member to
+  // decouple the watcher's life cycle from the NatPolicyLinux. This decoupling
+  // makes it possible to destroy the watcher before the loader's destructor is
+  // called (e.g. during Stop), since |watcher_| internally holds a reference to
+  // the loader and keeps it alive.
+  scoped_ptr<base::files::FilePathWatcher> watcher_;
+
+  // Records last known modification timestamp of |config_dir_|.
+  base::Time last_modification_file_;
+
+  // The wall clock time at which the last modification timestamp was
+  // recorded.  It's better to not assume the file notification time and the
+  // wall clock times come from the same source, just in case there is some
+  // non-local filesystem involved.
+  base::Time last_modification_clock_;
+
+  const FilePath config_dir_;
+
+  // Allows us to cancel any inflight FileWatcher events or scheduled reloads.
+  base::WeakPtrFactory<NatPolicyLinux> weak_factory_;
+};
+
+NatPolicy* NatPolicy::Create(base::MessageLoopProxy* message_loop_proxy) {
+  FilePath policy_dir(kPolicyDir);
+  return new NatPolicyLinux(message_loop_proxy, policy_dir);
+}
+
+}  // namespace policy_hack
+}  // namespace remoting
diff --git a/remoting/host/policy_hack/nat_policy_mac.mm b/remoting/host/policy_hack/nat_policy_mac.mm
new file mode 100644
index 0000000..25cf6e7
--- /dev/null
+++ b/remoting/host/policy_hack/nat_policy_mac.mm
@@ -0,0 +1,71 @@
+// Copyright (c) 2012 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 "remoting/host/policy_hack/nat_policy.h"
+
+#include <CoreFoundation/CoreFoundation.h>
+
+#include "base/compiler_specific.h"
+#include "base/mac/scoped_cftyperef.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop_proxy.h"
+#include "base/sys_string_conversions.h"
+#include "base/values.h"
+
+namespace remoting {
+namespace policy_hack {
+
+// The MacOS version does not watch files because it is accepted
+// practice on the Mac that the user must logout/login for policies to be
+// applied. This will actually pick up policies every
+// |kFallbackReloadDelayMinutes| which is sufficient for right now.
+class NatPolicyMac : public NatPolicy {
+ public:
+  explicit NatPolicyMac(base::MessageLoopProxy* message_loop_proxy)
+     : NatPolicy(message_loop_proxy) {
+  }
+
+  virtual ~NatPolicyMac() {
+  }
+
+ protected:
+  virtual void StartWatchingInternal() OVERRIDE {
+    Reload();
+  }
+
+  virtual void StopWatchingInternal() OVERRIDE {
+  }
+
+  virtual void Reload() OVERRIDE {
+    DCHECK(OnPolicyThread());
+    base::DictionaryValue policy;
+
+    CFStringRef policy_bundle_id = CFSTR("com.google.Chrome");
+    if (CFPreferencesAppSynchronize(policy_bundle_id)) {
+      base::mac::ScopedCFTypeRef<CFStringRef> policy_key(
+          base::SysUTF8ToCFStringRef(kNatPolicyName));
+      Boolean valid = false;
+      bool allowed = CFPreferencesGetAppBooleanValue(policy_key,
+                                                     policy_bundle_id,
+                                                     &valid);
+      if (valid) {
+        policy.SetBoolean(kNatPolicyName, allowed);
+      }
+    }
+
+    // Set policy. Policy must be set (even if it is empty) so that the
+    // default policy is picked up the first time reload is called.
+    UpdateNatPolicy(&policy);
+
+    // Reschedule task.
+    ScheduleFallbackReloadTask();
+  }
+};
+
+NatPolicy* NatPolicy::Create(base::MessageLoopProxy* message_loop_proxy) {
+  return new NatPolicyMac(message_loop_proxy);
+}
+
+}  // namespace policy_hack
+}  // namespace remoting
diff --git a/remoting/host/policy_hack/nat_policy_win.cc b/remoting/host/policy_hack/nat_policy_win.cc
new file mode 100644
index 0000000..1300b3b
--- /dev/null
+++ b/remoting/host/policy_hack/nat_policy_win.cc
@@ -0,0 +1,185 @@
+// Copyright (c) 2012 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.
+
+// Most of this code is copied from various classes in
+// src/chrome/browser/policy. In particular, look at
+//
+//   configuration_policy_provider_delegate_win.{h,cc}
+//   configuration_policy_loader_win.{h,cc}
+//
+// This is a reduction of the functionality in those classes.
+
+#include "remoting/host/policy_hack/nat_policy.h"
+
+#include <userenv.h>
+
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop_proxy.h"
+#include "base/string16.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/utf_string_conversions.h"
+#include "base/values.h"
+#include "base/win/object_watcher.h"
+#include "base/win/registry.h"
+
+// userenv.dll is required for RegisterGPNotification().
+#pragma comment(lib, "userenv.lib")
+
+using base::win::RegKey;
+
+namespace remoting {
+namespace policy_hack {
+
+namespace {
+
+const wchar_t kRegistrySubKey[] = L"SOFTWARE\\Policies\\Google\\Chrome";
+
+}  // namespace
+
+class NatPolicyWin :
+  public NatPolicy,
+  public base::win::ObjectWatcher::Delegate {
+ public:
+  explicit NatPolicyWin(base::MessageLoopProxy* message_loop_proxy)
+      : NatPolicy(message_loop_proxy),
+        user_policy_changed_event_(false, false),
+        machine_policy_changed_event_(false, false),
+        user_policy_watcher_failed_(false),
+        machine_policy_watcher_failed_(false) {
+  }
+
+  virtual ~NatPolicyWin() {
+  }
+
+  virtual void StartWatchingInternal() OVERRIDE {
+    DCHECK(OnPolicyThread());
+
+    if (!RegisterGPNotification(user_policy_changed_event_.handle(), false)) {
+      PLOG(WARNING) << "Failed to register user group policy notification";
+      user_policy_watcher_failed_ = true;
+    }
+
+    if (!RegisterGPNotification(machine_policy_changed_event_.handle(), true)) {
+      PLOG(WARNING) << "Failed to register machine group policy notification.";
+      machine_policy_watcher_failed_ = true;
+    }
+
+    Reload();
+  }
+
+  virtual void StopWatchingInternal() OVERRIDE {
+    DCHECK(OnPolicyThread());
+
+    if (!UnregisterGPNotification(user_policy_changed_event_.handle())) {
+      PLOG(WARNING) << "Failed to unregister user group policy notification";
+    }
+
+    if (!UnregisterGPNotification(machine_policy_changed_event_.handle())) {
+      PLOG(WARNING) <<
+          "Failed to unregister machine group policy notification.";
+    }
+
+    user_policy_watcher_.StopWatching();
+    machine_policy_watcher_.StopWatching();
+  }
+
+ private:
+  // Updates the watchers and schedules the reload task if appropriate.
+  void SetupWatches() {
+    DCHECK(OnPolicyThread());
+
+    if (!user_policy_watcher_failed_ &&
+        !user_policy_watcher_.GetWatchedObject() &&
+        !user_policy_watcher_.StartWatching(
+            user_policy_changed_event_.handle(), this)) {
+      LOG(WARNING) << "Failed to start watch for user policy change event";
+      user_policy_watcher_failed_ = true;
+    }
+
+    if (!machine_policy_watcher_failed_ &&
+        !machine_policy_watcher_.GetWatchedObject() &&
+        !machine_policy_watcher_.StartWatching(
+            machine_policy_changed_event_.handle(), this)) {
+      LOG(WARNING) << "Failed to start watch for machine policy change event";
+      machine_policy_watcher_failed_ = true;
+     }
+
+    if (user_policy_watcher_failed_ || machine_policy_watcher_failed_) {
+      ScheduleFallbackReloadTask();
+    }
+  }
+
+  bool GetRegistryPolicyInteger(const string16& value_name,
+                                uint32* result) const {
+    DWORD value = 0;
+    RegKey policy_key(HKEY_LOCAL_MACHINE, kRegistrySubKey, KEY_READ);
+    if (policy_key.ReadValueDW(value_name.c_str(), &value) == ERROR_SUCCESS) {
+      *result = value;
+      return true;
+    }
+
+    if (policy_key.Open(HKEY_CURRENT_USER, kRegistrySubKey, KEY_READ) ==
+        ERROR_SUCCESS) {
+      if (policy_key.ReadValueDW(value_name.c_str(), &value) == ERROR_SUCCESS) {
+        *result = value;
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool GetRegistryPolicyBoolean(const string16& value_name,
+                                bool* result) const {
+    uint32 local_result = 0;
+    bool ret = GetRegistryPolicyInteger(value_name, &local_result);
+    if (ret)
+      *result = local_result != 0;
+    return ret;
+  }
+
+  base::DictionaryValue* Load() {
+    base::DictionaryValue* policy = new base::DictionaryValue();
+
+    bool bool_value;
+    const string16 name(ASCIIToUTF16(kNatPolicyName));
+    if (GetRegistryPolicyBoolean(name, &bool_value)) {
+      policy->SetBoolean(kNatPolicyName, bool_value);
+    }
+
+    return policy;
+  }
+
+  // Post a reload notification and update the watch machinery.
+  void Reload() {
+    DCHECK(OnPolicyThread());
+    SetupWatches();
+    scoped_ptr<DictionaryValue> new_policy(Load());
+    UpdateNatPolicy(new_policy.get());
+  }
+
+  // ObjectWatcher::Delegate overrides:
+  virtual void OnObjectSignaled(HANDLE object) {
+    DCHECK(OnPolicyThread());
+    DCHECK(object == user_policy_changed_event_.handle() ||
+           object == machine_policy_changed_event_.handle())
+        << "unexpected object signaled policy reload, obj = "
+        << std::showbase << std::hex << object;
+    Reload();
+  }
+
+  base::WaitableEvent user_policy_changed_event_;
+  base::WaitableEvent machine_policy_changed_event_;
+  base::win::ObjectWatcher user_policy_watcher_;
+  base::win::ObjectWatcher machine_policy_watcher_;
+  bool user_policy_watcher_failed_;
+  bool machine_policy_watcher_failed_;
+};
+
+NatPolicy* NatPolicy::Create(base::MessageLoopProxy* message_loop_proxy) {
+  return new NatPolicyWin(message_loop_proxy);
+}
+
+}  // namespace policy_hack
+}  // namespace remoting