Remove obsolete app_list Linux code.

chrome/browser/ui/app_list/fast_show_pickler.h

-// 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 CHROME_BROWSER_UI_APP_LIST_FAST_SHOW_PICKLER_H_
-#define CHROME_BROWSER_UI_APP_LIST_FAST_SHOW_PICKLER_H_
-
-#include <memory>
-#include <string>
-
-#include "base/pickle.h"
-#include "ui/app_list/app_list_model.h"
-
-// Functions for pickling/unpickling AppListModel for fast show. Fast show is
-// where the app list is put on the screen using data retrieved from a cache
-// before the extension system has loaded.
-class FastShowPickler {
- public:
-  // The version that this pickler understands.
-  static const int kVersion;
-
-  // Pickles a subset of the data in |model| that is useful for doing a fast
-  // show of the app list.
-  static std::unique_ptr<base::Pickle> PickleAppListModelForFastShow(
-      app_list::AppListModel* model);
-
-  // Given a Pickle created by PickleAppListModelForFastShow(), this creates an
-  // AppListModel that represents it.
-  static std::unique_ptr<app_list::AppListModel>
-  UnpickleAppListModelForFastShow(base::Pickle* pickle);
-
-  // Copies parts that are needed to show the app list quickly on startup from
-  // |src| to |dest|.
-  static void CopyOver(
-      app_list::AppListModel* src, app_list::AppListModel* dest);
-
- private:
-  // Private static methods allow friend access to AppListItem methods.
-  static std::unique_ptr<app_list::AppListItem> UnpickleAppListItem(
-      base::PickleIterator* it);
-  static bool PickleAppListItem(base::Pickle* pickle,
-                                app_list::AppListItem* item);
-  static void CopyOverItem(app_list::AppListItem* src_item,
-                           app_list::AppListItem* dest_item);
-};
-
-#endif  // CHROME_BROWSER_UI_APP_LIST_FAST_SHOW_PICKLER_H_