Changed DefaultAdapter to RunCallbackOnAdapterReady function.

chrome/browser/chromeos/system/ash_system_tray_delegate.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 "chrome/browser/chromeos/system/ash_system_tray_delegate.h"
 
 #include <algorithm>
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
@@ skipping 252 matching lines @@
     input_method::GetInputMethodManager()->AddObserver(this);
 
     system::TimezoneSettings::GetInstance()->AddObserver(this);
 
     if (SystemKeyEventListener::GetInstance())
       SystemKeyEventListener::GetInstance()->AddCapsLockObserver(this);
 
     network_icon_->SetResourceColorTheme(NetworkMenuIcon::COLOR_LIGHT);
     network_icon_dark_->SetResourceColorTheme(NetworkMenuIcon::COLOR_DARK);
 
-    bluetooth_adapter_ = device::BluetoothAdapterFactory::DefaultAdapter();
+    device::BluetoothAdapterFactory::RunCallbackOnAdapterReady(
+        base::Bind(&SystemTrayDelegate::InitializeOnAdapterReady,
+                   ui_weak_ptr_factory_->GetWeakPtr()));
+  }
+
+  void InitializeOnAdapterReady(
+      scoped_refptr<device::BluetoothAdapter> adapter) {
+    bluetooth_adapter_ = adapter;
+    CHECK(bluetooth_adapter_);

[Nikita (slow), 2013/01/10 10:29:55]

You're passing adapter as a weak pointer so NULL could be passed?

[youngki, 2013/01/10 18:58:54]

Yes, a weak pointer passed from BluetoothAdapterFactory. And NULL would be
passed if the BluetoothAdapterFactory::RunCallbackOnAdapterReady() is called on
other platforms (i.e. OSX).

[Nikita (slow), 2013/01/11 11:15:09]

So do you actually need a CHECK here or would it be enough to return if
bluetooth_adapter_ hasn't been specified?

[youngki, 2013/01/11 13:18:47]

I think we need a check here since bluetooth_adapter_ being NULL in this case
should not happen. And many parts in this file depend on the fact that
bluetooth_adapter_ is properly initialized.

[Nikita (slow), 2013/01/11 15:34:21]

I don't want to block this CL but it seems a bit strange that on the one hand
you allow the possibility of passing NULL to this method (because weak pointer
is used) and at the same time you have a strict requirement here (CHECK) that
makes such situations invalid.

[youngki, 2013/01/11 16:47:56]

That's a valid concern; I appreciate you point it out.

I still think we should put CHECK here;
device::BluetoothAdapterFactory::RunCallbackOnAdapterReady() is a
platform-independent call. This passes a bluetooth adapter pointer if the
bluetooth functionalities are supported in the currentplatform, otherwise it
passes NULL. Since ChromeOs is a supported platform, BluetoothAdapterFactory
should always pass a bluetooth adapter pointer to this method. So, although
there is a possibility of passing NULL because of generality of the
BluetoothAdapterFactory, this shouldn't pass NULL in this specific case because
this code only runs on ChromeOs, and we'd like to make that explicit by having
CHECK here.

     bluetooth_adapter_->AddObserver(this);
 
     local_state_registrar_.Init(g_browser_process->local_state());
 
     UpdateSessionStartTime();
     UpdateSessionLengthLimit();
 
     local_state_registrar_.Add(
         prefs::kSessionStartTime,
         base::Bind(&SystemTrayDelegate::UpdateSessionStartTime,
@@ skipping 1115 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(SystemTrayDelegate);
 };
 
 }  // namespace
 
 ash::SystemTrayDelegate* CreateSystemTrayDelegate() {
   return new chromeos::SystemTrayDelegate();
 }
 
 }  // namespace chromeos