No Easy unlock if bluetooth is not available.

chrome/browser/signin/easy_unlock_service.h

 // Copyright 2014 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 CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_H_
 #define CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_H_
 
 #include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 class Profile;
 
@@ skipping 10 matching lines @@
 
   // Launches Easy Unlock Setup app.
   void LaunchSetup();
 
   // Whether easy unlock is allowed to be used. If the controlling preference
   // is set (from policy), this returns the preference value. Otherwise, it is
   // permitted either the flag is enabled or its field trial is enabled.
   bool IsAllowed();
 
  private:
+  // A class to detect whether a bluetooth adapter is present.
+  class BluetoothDetector;

[Ilya Sherman, 2014/08/14 07:29:41]

Do we really need to implement this code here, or is there perhaps already
similar code elsewhere?  According to the bug report, we already hide some
settings if there is no Bluetooth adapter present...

[xiyuan, 2014/08/14 20:27:44]

The Bluetooth settings logic is baked into its webui handler and it is what
BluetoothDetector does.

I would prefer to have the logic here instead of in the webui handler so that we
don't even need to load component app and save a bit more resources.

+
   void Initialize();
   void LoadApp();
   void UnloadApp();
+  void CheckIsAllowed();
   void OnPrefsChanged();
+  void OnBluetoothAdapterPresentChanged();

[Ilya Sherman, 2014/08/14 07:29:42]

nit: Please document at least the new methods.

[xiyuan, 2014/08/14 20:27:44]

Done.

 
   Profile* profile_;
   PrefChangeRegistrar registrar_;
+  scoped_ptr<BluetoothDetector> bluetooth_detector_;

[Ilya Sherman, 2014/08/14 07:29:42]

Hmm, is this a scoped_ptr just so that you can keep the BluetoothDetector
definition out of the header file?  I'm not sure that's needed; but either way
is fine I guess.

[xiyuan, 2014/08/14 20:27:44]

Yep. I prefer to put as little as possible details in header.

   base::WeakPtrFactory<EasyUnlockService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(EasyUnlockService);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_H_