Slightly modified ETA computation algorithm. Also modified UI of the

chrome/browser/chromeos/login/update_screen_actor.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 CHROME_BROWSER_CHROMEOS_LOGIN_UPDATE_SCREEN_ACTOR_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_UPDATE_SCREEN_ACTOR_H_
 
 #include "base/time.h"
 
 namespace chromeos {
 
 class UpdateScreenActor {
  public:
+  // Indices for corresponding info messages during update stage.
+  enum ProgressMessage {
+    PROGRESS_MESSAGE_UPDATE_AVAILABLE = 0,
+    PROGRESS_MESSAGE_INSTALLING_UPDATE,
+    PROGRESS_MESSAGE_VERIFYING,
+    PROGRESS_MESSAGE_FINALIZING
+  };
+
   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;
 
   // Hides the screen.
   virtual void Hide() = 0;
 
   virtual void PrepareToShow() = 0;
 
   // Shows manual reboot info message.
   virtual void ShowManualRebootInfo() = 0;
 
   // Sets current progress in percents.
   virtual void SetProgress(int progress) = 0;
 
   // Shows estimated time left message.
-  virtual void ShowEstimatedTimeLeft(bool enable) = 0;
+  virtual void ShowEstimatedTimeLeft(bool visible) = 0;
 
   // Sets current estimation for time left in the downloading stage.
   virtual void SetEstimatedTimeLeft(const base::TimeDelta& time) = 0;
 
+  // Shows message under progress bar.
+  virtual void ShowProgressMessage(bool visible) = 0;
+
+  // Sets message under progress bar.
+  virtual void SetProgressMessage(ProgressMessage message) = 0;
+
   // Shows screen curtains.
-  virtual void ShowCurtain(bool enable) = 0;
-
-  // Shows label for "Preparing updates" state.
-  virtual void ShowPreparingUpdatesInfo(bool visible) = 0;
+  virtual void ShowCurtain(bool visible) = 0;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_UPDATE_SCREEN_ACTOR_H_