Remove the most obvious dead code from message center.

ui/message_center/views/message_popup_bubble.h

Index: ui/message_center/views/message_popup_bubble.h
diff --git a/ui/message_center/views/message_popup_bubble.h b/ui/message_center/views/message_popup_bubble.h
deleted file mode 100644
index f8493168f00b2c8a3b6597b064c997e6e405845a..0000000000000000000000000000000000000000
--- a/ui/message_center/views/message_popup_bubble.h
+++ /dev/null
@@ -1,54 +0,0 @@
-// 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 UI_MESSAGE_CENTER_VIEWS_MESSAGE_POPUP_BUBBLE_H_
-#define UI_MESSAGE_CENTER_VIEWS_MESSAGE_POPUP_BUBBLE_H_
-
-#include <map>
-#include <set>
-#include <string>
-
-#include "base/timer/timer.h"
-#include "ui/message_center/message_center_export.h"
-#include "ui/message_center/views/message_bubble_base.h"
-
-namespace message_center {
-
-class PopupBubbleContentsView;
-
-// Bubble for popup notifications.
-class MESSAGE_CENTER_EXPORT MessagePopupBubble : public MessageBubbleBase {
- public:
-  explicit MessagePopupBubble(MessageCenter* message_center);
-
-  virtual ~MessagePopupBubble();
-
-  // Overridden from MessageBubbleBase:
-  virtual views::TrayBubbleView::InitParams GetInitParams(
-      views::TrayBubbleView::AnchorAlignment anchor_alignment) OVERRIDE;
-  virtual void InitializeContents(views::TrayBubbleView* bubble_view) OVERRIDE;
-  virtual void OnBubbleViewDestroyed() OVERRIDE;
-  virtual void UpdateBubbleView() OVERRIDE;
-  virtual void OnMouseEnteredView() OVERRIDE;
-  virtual void OnMouseExitedView() OVERRIDE;
-
-   size_t NumMessageViewsForTest() const;
-
- private:
-   class AutocloseTimer;
-
-  void OnAutoClose(const std::string& id);
-
-  void DeleteTimer(const std::string& id);
-
-  std::map<std::string, AutocloseTimer*> autoclose_timers_;
-  PopupBubbleContentsView* contents_view_;
-  std::set<std::string> popup_ids_;
-
-  DISALLOW_COPY_AND_ASSIGN(MessagePopupBubble);
-};
-
-}  // namespace message_center
-
-#endif // UI_MESSAGE_CENTER_VIEWS_MESSAGE_POPUP_BUBBLE_H_