app_list: Improve initial icon loading.

ui/app_list/apps_grid_view.cc

 // 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.
 
 #include "ui/app_list/apps_grid_view.h"
 
 #include <algorithm>
 
-#include "ui/app_list/app_list_item_model.h"
 #include "ui/app_list/app_list_item_view.h"
 #include "ui/app_list/apps_grid_view_delegate.h"
 #include "ui/app_list/page_switcher.h"
 #include "ui/app_list/pagination_model.h"
 #include "ui/app_list/pulsing_block_view.h"
 #include "ui/base/animation/animation.h"
 #include "ui/base/events/event.h"
 #include "ui/views/border.h"
 #include "ui/views/view_model_utils.h"
 #include "ui/views/widget/widget.h"
@@ skipping 296 matching lines @@
       selected_view_ = NULL;
 
     if (drag_view_ == child)
       EndDrag(true);
 
     bounds_animator_.StopAnimatingView(child);
   }
 }
 
 void AppsGridView::Update() {
-  selected_view_ = NULL;
+  DCHECK(!selected_view_ && !drag_view_);
+
   view_model_.Clear();
   if (model_ && model_->apps()->item_count())
     ListItemsAdded(0, model_->apps()->item_count());
 }
 
 void AppsGridView::UpdatePaging() {
   if (!view_model_.view_size() || !tiles_per_page()) {
     pagination_model_->SetTotalPages(0);
     return;
   }
@@ skipping 417 matching lines @@
     Layout();
 }
 
 void AppsGridView::OnAppListModelStatusChanged() {
   UpdatePulsingBlockViews();
   Layout();
   SchedulePaint();
 }
 
 }  // namespace app_list