Added back button when in folder view.

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 63 matching lines @@
 
   // Moves focus forward/backwards in response to TAB.
   bool MoveTabFocus(bool move_backwards);
 
   // Moves focus to contents or SearchBox and unselects buttons.
   void ResetTabFocus(bool on_contents);
 
   // Sets voice label for Back button depending on whether a folder is open.
   void SetBackButtonLabel(bool folder);
 
+  // Swaps the google icon with the back button.
+  void ShowBackOrGoogleIcon(bool show_back_button);
+
   // Overridden from views::View:
   bool OnMouseWheel(const ui::MouseWheelEvent& event) override;
   void OnEnabledChanged() override;
   const char* GetClassName() const override;
 
  private:
   // Updates model text and selection model with current Textfield info.
   void UpdateModel();
 
   // Fires query change notification.
@@ skipping 34 matching lines @@
 
   // Whether the fullscreen app list feature is enabled.
   const bool is_fullscreen_app_list_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(SearchBoxView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_SEARCH_BOX_VIEW_H_