[cros] check for updates in WebUI OOBE can be cancelled in dev builds.

chrome/browser/chromeos/login/update_screen_actor.h

Index: chrome/browser/chromeos/login/update_screen_actor.h
diff --git a/chrome/browser/chromeos/login/update_screen_actor.h b/chrome/browser/chromeos/login/update_screen_actor.h
index aa345848ee8816f3e730f22625a5478cc03177ef..1c749568289b10c9c8975530cdc13d455e85cce3 100644
--- a/chrome/browser/chromeos/login/update_screen_actor.h
+++ b/chrome/browser/chromeos/login/update_screen_actor.h
@@ -13,8 +13,19 @@ class ScreenObserver;
 
 class UpdateScreenActor {
  public:
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+    // Force cancel update.
+    virtual void CancelUpdate() = 0;
+    virtual void OnActorDestroyed(UpdateScreenActor* actor) = 0;
+  };
+
   virtual ~UpdateScreenActor() {}
 
+  // Sets screen this actor belongs to.
+  virtual void SetDelegate(Delegate* screen) = 0;
+
   // Shows the screen.
   virtual void Show() = 0;