app_list: Enable level 1 of cpplint, be stricker.

ui/app_list/views/cached_label.h

 // 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.
 
 #ifndef UI_APP_LIST_VIEWS_CACHED_LABEL_H_
 #define UI_APP_LIST_VIEWS_CACHED_LABEL_H_
 
 #include "ui/gfx/image/image_skia.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/view.h"
@@ skipping 10 matching lines @@
   CachedLabel();
 
   // Have the next call to OnPaint() update the backing image.
   void Invalidate() { needs_repaint_ = true; }
 
   // Calls the base label's OnPaint() to paint into a backing image.
   void PaintToBackingImage();
 
 #if defined(OS_WIN)
   // Overridden from views::View:
-  virtual void OnPaint(gfx::Canvas* canvas) override;
+  void OnPaint(gfx::Canvas* canvas) override;
 #endif
 
   // Overridden from ui::LayerDelegate:
   void OnDeviceScaleFactorChanged(float device_scale_factor) override;
 
  private:
   bool needs_repaint_;
   gfx::ImageSkia image_;
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_CACHED_LABEL_H_