Implemented Asynchronous Initialization of BluetoothAdapter.

device/bluetooth/bluetooth_adapter_factory.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_ADAPTER_FACTORY_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_FACTORY_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 
 namespace device {
 
 // BluetoothAdapterFactory is a class that contains static methods, which
 // instantiate either a specific Bluetooth adapter, or the generic "default
 // adapter" which may change depending on availability.
 class BluetoothAdapterFactory {
  public:
+  typedef base::Callback<void(scoped_refptr<BluetoothAdapter> adapter)>
+      AdapterCallback;
+
   // Returns true if the Bluetooth adapter is available for the current
   // platform.
   static bool IsBluetoothAdapterAvailable();
 
-  // Runs the callback with the shared instance for the default adapter when the
-  // adapter is available to be used.
-  static void RunCallbackOnAdapterReady(
-      const BluetoothAdapter::AdapterCallback& callback);
+  // Returns the shared instance of the default adapter, creating and
+  // initializing it if necessary. |callback| is called with the adapter
+  // instance passed only once the adapter is fully initialized and ready to
+  // use.
+  static void GetAdapter(const AdapterCallback& callback);
 
-  // Returns the shared instance of the adapter that has already been created.
+  // Returns the shared instance of the adapter that has already been created,
+  // but may or may not have been initialized.
   // It returns NULL if no adapter has been created at the time.
-  static scoped_refptr<BluetoothAdapter> GetAdapter();
+  static scoped_refptr<BluetoothAdapter> MaybeGetAdapter();
 
   // Creates an instance for a specific adapter at address |address|.
   static BluetoothAdapter* Create(const std::string& address);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_FACTORY_H_