Implemented BluetoothTaskManagerWin class.

device/bluetooth/bluetooth_polling_thread_win.h

+// 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 DEVICE_BLUETOOTH_BLUETOOTH_POLLING_THREAD_WIN_H_
+#define DEVICE_BLUETOOTH_BLUETOOTH_POLLING_THREAD_WIN_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/synchronization/cancellation_flag.h"
+#include "base/threading/thread.h"
+#include "base/threading/thread_checker.h"
+
+namespace device {
+
+// A thread dedicated to perform blocking bluetooth APIs on Windows.
+class BluetoothPollingThreadWin : public base::Thread {
+ public:
+  struct AdapterState {
+    std::string name;
+    std::string address;
+    bool powered;
+  };
+
+  class Observer {
+   public:
+    virtual ~Observer() {}
+
+    // This will always be called on the UI thread.
+    virtual void AdapterStateChanged(const AdapterState& state) {}
+  };
+
+  BluetoothPollingThreadWin();
+  virtual ~BluetoothPollingThreadWin();
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  void Init();
+
+ private:
+  // Called periodically to get the latest state of the Bluetooth Adapter from
+  // the Windows APIs. Posts another call to PollAdapter unless
+  // |cancellation_flag_| is set.

[bryeung, 2012/12/10 19:15:35]

Include a comment here about why the weak_ptr is necessary.  Something like:
"This methods requires |weak_ptr_for_ui_thread| because OnAdapterStateChanged
must be called on a weak reference to this object on the UI thread.  We cannot
create the weak reference on this thread because weak_ptrs cannot be
dereferenced from a thread different than their owning thread."

+  void PollAdapter(base::WeakPtr<BluetoothPollingThreadWin> weak_ptr);
+
+  // Notify all Observers of updated AdapterState. Should only be called on the
+  // UI thread.
+  void OnAdapterStateChanged(const AdapterState* state);
+
+  static const int kPollIntervalMs;
+
+  // Polling will be canceled when BluetoothPollingThread terminates.
+  base::CancellationFlag cancellation_flag_;
+
+  // Checks that PollAdapter runs on BluetoothPollingThread.
+  base::ThreadChecker thread_checker_;
+
+  // List of observers interested in event notifications.
+  ObserverList<Observer> observers_;
+
+  // NOTE: This should remain the last member so it'll be destroyed and
+  // invalidate its weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<BluetoothPollingThreadWin> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(BluetoothPollingThreadWin);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_BLUETOOTH_BLUETOOTH_POLLING_THREAD_WIN_H_