win: Ref-counted classes should have non-public destructors.

ui/gl/gl_context_wgl.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_GL_GL_CONTEXT_WGL_H_
 #define UI_GL_GL_CONTEXT_WGL_H_
 
 #include <string>
 
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gl/gl_context.h"
 
 namespace gfx {
 
 class GLSurface;
 
 // This class is a wrapper around a GL context.
 class GLContextWGL : public GLContextReal {
  public:
   explicit GLContextWGL(GLShareGroup* share_group);
-  ~GLContextWGL() override;
 
   // Implement GLContext.
   bool Initialize(GLSurface* compatible_surface,
                   GpuPreference gpu_preference) override;
   void Destroy() override;
   bool MakeCurrent(GLSurface* surface) override;
   void ReleaseCurrent(GLSurface* surface) override;
   bool IsCurrent(GLSurface* surface) override;
   void* GetHandle() override;
   void OnSetSwapInterval(int interval) override;
   std::string GetExtensions() override;
 
  private:
+  ~GLContextWGL() override;
+
   HGLRC context_;
 
   DISALLOW_COPY_AND_ASSIGN(GLContextWGL);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_CONTEXT_WGL_H_