Remove some platform specific stuff from views.

ui/app_list/search/history_data_observer.h

Index: ui/app_list/search/history_data_observer.h
diff --git a/ui/app_list/search/history_data_observer.h b/ui/app_list/search/history_data_observer.h
deleted file mode 100644
index cf77cd6fd2383f5eda90a05a4eb3414a8b94415a..0000000000000000000000000000000000000000
--- a/ui/app_list/search/history_data_observer.h
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2013 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_APP_LIST_SEARCH_HISTORY_DATA_OBSERVER_H_
-#define UI_APP_LIST_SEARCH_HISTORY_DATA_OBSERVER_H_
-
-#include "ui/app_list/app_list_export.h"
-
-namespace app_list {
-
-class APP_LIST_EXPORT HistoryDataObserver {
- public:
-  // Invoked when the data is loaded from underlying store.
-  virtual void OnHistoryDataLoadedFromStore() = 0;
-
- protected:
-  virtual ~HistoryDataObserver() {}
-};
-
-}  // namespace app_list
-
-#endif  // UI_APP_LIST_SEARCH_HISTORY_DATA_OBSERVER_H_