RefCounted types should not have public destructors, delegate cleanup

content/common/gpu/gpu_watchdog.h

 // Copyright (c) 2011 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 CONTENT_COMMON_GPU_GPU_WATCHDOG_H_
 #define CONTENT_COMMON_GPU_GPU_WATCHDOG_H_
 
 // Interface for objects that monitor the a GPUProcessor's progress. The
 // GPUProcessor will regularly invoke CheckArmed.
 class GpuWatchdog {
  public:
-  GpuWatchdog() {
-  }
+  virtual void CheckArmed() = 0;
 
-  virtual ~GpuWatchdog() {
-  };
-
-  virtual void CheckArmed() = 0;
+ protected:
+  GpuWatchdog() {}
+  virtual ~GpuWatchdog() {};
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GpuWatchdog);
 };
 
 #endif  // CONTENT_COMMON_GPU_GPU_WATCHDOG_H_