Added back button when in folder view.

ui/app_list/views/app_list_folder_view.cc

 // 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.
 
 #include "ui/app_list/views/app_list_folder_view.h"
 
 #include <algorithm>
 
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/app_list/app_list_constants.h"
@@ skipping 93 matching lines @@
   UpdateFolderNameVisibility(true);
 
   ui::ScopedLayerAnimationSettings animation(layer()->GetAnimator());
   animation.SetTweenType(
       show ? kFolderFadeInTweenType : kFolderFadeOutTweenType);
   animation.AddObserver(this);
   animation.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
       show ? kFolderTransitionInDurationMs : kFolderTransitionOutDurationMs));
 
   layer()->SetOpacity(show ? 1.0f : 0.0f);
+  app_list_main_view_->search_box_view()->ShowBackOrGoogleIcon(show);
 }
 
 gfx::Size AppListFolderView::CalculatePreferredSize() const {
   const gfx::Size header_size = folder_header_view_->GetPreferredSize();
   const gfx::Size grid_size = items_grid_view_->GetPreferredSize();
   int width = std::max(header_size.width(), grid_size.width());
   int height = header_size.height() + grid_size.height();
   return gfx::Size(width, height);
 }
 
@@ skipping 219 matching lines @@
 void AppListFolderView::GiveBackFocusToSearchBox() {
   app_list_main_view_->search_box_view()->search_box()->RequestFocus();
 }
 
 void AppListFolderView::SetItemName(AppListFolderItem* item,
                                     const std::string& name) {
   model_->SetItemName(item, name);
 }
 
 }  // namespace app_list