app_list: Enable level 1 of cpplint, be stricker.

ui/app_list/views/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/views/apps_grid_view.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 
@@ skipping 273 matching lines @@
 
   void EndDragExternally() {
     CancelDrag();
     DCHECK(drag_view_);
     drag_view_->SetVisible(true);
     drag_view_ = NULL;
   }
 
  private:
   // Overridden from ui::DragSourceWin.
-  virtual void OnDragSourceCancel() override {
-    canceled_ = true;
-  }
+  void OnDragSourceCancel() override { canceled_ = true; }
 
-  virtual void OnDragSourceDrop() override {
-  }
+  void OnDragSourceDrop() override {}
 
-  virtual void OnDragSourceMove() override {
+  void OnDragSourceMove() override {
     grid_view_->UpdateDrag(AppsGridView::MOUSE, GetCursorInGridViewCoords());
   }
 
   void SetupExchangeData(ui::OSExchangeData* data) {
     data->SetFilename(shortcut_path_);
     gfx::ImageSkia image(drag_view_->GetDragImage());
     gfx::Size image_size(image.size());
     drag_utils::SetDragImageOnDataObject(
         image,
         drag_view_offset_ - drag_view_->GetDragImageOffset(),
@@ skipping 1859 matching lines @@
 
 void AppsGridView::SetAsFolderDroppingTarget(const Index& target_index,
                                              bool is_target_folder) {
   AppListItemView* target_view =
       GetViewDisplayedAtSlotOnCurrentPage(target_index.slot);
   if (target_view)
     target_view->SetAsAttemptedFolderTarget(is_target_folder);
 }
 
 }  // namespace app_list