Remove old (dead) app list code.

ui/app_list/views/search_box_view.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 UI_APP_LIST_VIEWS_SEARCH_BOX_VIEW_H_
 #define UI_APP_LIST_VIEWS_SEARCH_BOX_VIEW_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 93 matching lines @@
 
   // Overridden from views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   // Overridden from views::MenuButtonListener:
   void OnMenuButtonClicked(views::MenuButton* source,
                            const gfx::Point& point,
                            const ui::Event* event) override;
 
   // Overridden from SearchBoxModelObserver:
-  void IconChanged() override;
   void SpeechRecognitionButtonPropChanged() override;
   void HintTextChanged() override;
   void SelectionModelChanged() override;
   void TextChanged() override;
 
   // Overridden from SpeechUIModelObserver:
   void OnSpeechRecognitionStateChanged(
       SpeechRecognitionState new_state) override;
 
   SearchBoxViewDelegate* delegate_;  // Not owned.
   AppListViewDelegate* view_delegate_;  // Not owned.
   AppListModel* model_;  // Owned by the profile-keyed service.
 
   std::unique_ptr<AppListMenuViews> menu_;
 
   views::View* content_container_;     // Owned by views hierarchy.
-  views::ImageView* icon_view_;  // Owned by views hierarchy.
   SearchBoxImageButton* back_button_;    // Owned by views hierarchy.
   SearchBoxImageButton* speech_button_;  // Owned by views hierarchy.
   views::MenuButton* menu_button_;  // Owned by views hierarchy.
   views::Textfield* search_box_;  // Owned by views hierarchy.
   views::View* contents_view_;  // Owned by views hierarchy.
 
   SearchBoxFocus focused_view_;  // Which element has TAB'd focus.
 
   DISALLOW_COPY_AND_ASSIGN(SearchBoxView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_SEARCH_BOX_VIEW_H_