Changed DefaultAdapter to RunCallbackOnAdapterReady function.

chrome/browser/chromeos/system/ash_system_tray_delegate.cc

Index: chrome/browser/chromeos/system/ash_system_tray_delegate.cc
diff --git a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
index 64ef92c61d8c01a46d949570c467563157749761..b666d5cb76e1199c78f0a356e87b031099439e22 100644
--- a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
+++ b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
@@ -270,7 +270,15 @@ class SystemTrayDelegate : public ash::SystemTrayDelegate,
     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());