Modify UpdateLibrary to use async RequestUpdateCheck call

chrome/browser/chromeos/login/update_screen.cc

Index: chrome/browser/chromeos/login/update_screen.cc
diff --git a/chrome/browser/chromeos/login/update_screen.cc b/chrome/browser/chromeos/login/update_screen.cc
index e39345c0ba9592b526876203e01e3695f68a9af5..0ef0955ead6bd653840fe2913450b420af7d2820 100644
--- a/chrome/browser/chromeos/login/update_screen.cc
+++ b/chrome/browser/chromeos/login/update_screen.cc
@@ -134,6 +134,16 @@ void UpdateScreen::UpdateStatusChanged(UpdateLibrary* library) {
   }
 }
 
+namespace {
+void update_callback(void* user_data, UpdateResult result, const char* msg) {

[altimofeev, 2011/03/09 10:42:27]

nit: Please, use BumpyCase for the function's name. Also, please, add comment or
use more specific function's name.

[stevenjb, 2011/03/10 01:23:16]

Oops. Relapse. Done.

+  if (result != UPDATE_RESULT_SUCCESS) {
+    DCHECK(user_data);
+    UpdateScreen* screen = static_cast<UpdateScreen*>(user_data);
+    screen->ExitUpdate(UpdateScreen::REASON_UPDATE_INIT_FAILED);

[altimofeev, 2011/03/09 10:42:27]

What if update screen has been destroyed before this callback is fired? (e.g.
user skips update).

[stevenjb, 2011/03/10 01:23:16]

Good catch. I will add an instance list to check. Shouldn't need anything fancy
since this all happens on the same thread.

+  }
+}
+}  // namespace
+
 void UpdateScreen::StartUpdate() {
   // Reset view if view was created.
   if (view()) {
@@ -149,9 +159,8 @@ void UpdateScreen::StartUpdate() {
   } else {
     CrosLibrary::Get()->GetUpdateLibrary()->AddObserver(this);
     VLOG(1) << "Initiate update check";
-    if (!CrosLibrary::Get()->GetUpdateLibrary()->CheckForUpdate()) {
-      ExitUpdate(REASON_UPDATE_INIT_FAILED);
-    }
+    CrosLibrary::Get()->GetUpdateLibrary()->RequestUpdate(
+        update_callback, this);
   }
 }