chrome.bluetooth API improvements.

device/bluetooth/bluetooth_socket_thread_win.cc

+// 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 "device/bluetooth/bluetooth_socket_thread_win.h"
+
+#include "base/lazy_instance.h"
+#include "base/sequenced_task_runner.h"
+#include "base/threading/thread.h"
+
+namespace device {
+
+base::LazyInstance<scoped_refptr<BluetoothSocketThreadWin> > g_instance =
+    LAZY_INSTANCE_INITIALIZER;
+
+// static
+scoped_refptr<BluetoothSocketThreadWin> BluetoothSocketThreadWin::Get() {
+  if (!g_instance.Get().get()) {
+    g_instance.Get() = new BluetoothSocketThreadWin();
+  }
+  return g_instance.Get();
+}
+
+BluetoothSocketThreadWin::BluetoothSocketThreadWin()
+    : active_socket_count_(0) {}
+
+BluetoothSocketThreadWin::~BluetoothSocketThreadWin() {}
+
+void BluetoothSocketThreadWin::OnSocketActivate() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  active_socket_count_++;
+  EnsureStarted();
+}
+
+void BluetoothSocketThreadWin::OnSocketDeactivate() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  active_socket_count_--;
+  if (active_socket_count_ == 0 && thread_) {
+    thread_->Stop();
+    thread_.reset(NULL);
+    task_runner_ = NULL;
+  }
+}
+
+void BluetoothSocketThreadWin::EnsureStarted() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (thread_)
+    return;
+
+  base::Thread::Options thread_options;
+  thread_options.message_loop_type = base::MessageLoop::TYPE_IO;
+  thread_.reset(new base::Thread("BluetoothSocketThreadWin"));
+  thread_->StartWithOptions(thread_options);
+  task_runner_ = thread_->message_loop_proxy();
+}
+
+scoped_refptr<base::SequencedTaskRunner> BluetoothSocketThreadWin::task_runner()
+    const {
+  DCHECK(active_socket_count_ > 0);
+  DCHECK(thread_);
+  DCHECK(task_runner_);
+
+  return task_runner_;
+}
+
+}  // namespace device