RefCounted types should not have public destructors, chromeos edition

chrome/browser/chromeos/low_memory_observer.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 "chrome/browser/chromeos/low_memory_observer.h"
 
 #include <fcntl.h>
 
 #include "base/bind.h"
 #include "base/chromeos/chromeos_version.h"
@@ skipping 30 matching lines @@
 // kLowMemoryCheckTimeoutMs milliseconds and then start watching again to see
 // if we're still in a low memory state.  This is to keep from discarding all
 // tabs the first time we enter the state, because it takes time for the
 // tabs to deallocate their memory.  A timer isn't the perfect solution, but
 // without any reliable indicator that a tab has had all its parts deallocated,
 // it's the next best thing.
 class LowMemoryObserverImpl
     : public base::RefCountedThreadSafe<LowMemoryObserverImpl> {
  public:
   LowMemoryObserverImpl() : watcher_delegate_(this), file_descriptor_(-1) {}
-  ~LowMemoryObserverImpl() {
-    StopObservingOnFileThread();
-  }
 
   // Start watching the low memory file for readability.
   // Calls to StartObserving should always be matched with calls to
   // StopObserving.  This method should only be called from the FILE thread.
   void StartObservingOnFileThread();
 
   // Stop watching the low memory file for readability.
   // May be safely called if StartObserving has not been called.
   // This method should only be called from the FILE thread.
   void StopObservingOnFileThread();
 
  private:
+  friend class base::RefCountedThreadSafe<LowMemoryObserverImpl>;
+
+  ~LowMemoryObserverImpl() {
+    StopObservingOnFileThread();
+  }
+
   // Start a timer to resume watching the low memory file descriptor.
   void ScheduleNextObservation();
 
   // Actually start watching the file descriptor.
   void StartWatchingDescriptor();
 
   // Delegate to receive events from WatchFileDescriptor.
   class FileWatcherDelegate : public MessageLoopForIO::Watcher {
    public:
     explicit FileWatcherDelegate(LowMemoryObserverImpl* owner)
@@ skipping 105 matching lines @@
       base::Bind(&LowMemoryObserverImpl::StopObservingOnFileThread,
                  observer_.get()));
 }
 
 // static
 void LowMemoryObserver::SetLowMemoryMargin(int64 margin_mb) {
   content::ZygoteHost::GetInstance()->AdjustLowMemoryMargin(margin_mb);
 }
 
 }  // namespace chromeos