[Chromoting] Refactor the host policy watcher so that policies can easily be added.

remoting/host/policy_hack/nat_policy_mac.mm

-// 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/single_thread_task_runner.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(scoped_refptr<base::SingleThreadTaskRunner> task_runner)
-     : NatPolicy(task_runner) {
-  }
-
-  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(
-        scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
-  return new NatPolicyMac(task_runner);
-}
-
-}  // namespace policy_hack
-}  // namespace remoting