RefCounted types should not have public destructors, delegate cleanup

content/browser/device_orientation/provider.h

Index: content/browser/device_orientation/provider.h
diff --git a/content/browser/device_orientation/provider.h b/content/browser/device_orientation/provider.h
index a44128cf462a71d3094b331b6824c749eb6f7a1d..b93682e135ff74194c115dc3bfd21beb80174cc6 100644
--- a/content/browser/device_orientation/provider.h
+++ b/content/browser/device_orientation/provider.h
@@ -20,6 +20,9 @@ class CONTENT_EXPORT Provider : public base::RefCountedThreadSafe<Provider> {
     // An Observer must not synchronously call Provider::RemoveObserver
     // or Provider::AddObserver when this is called.
     virtual void OnOrientationUpdate(const Orientation& orientation) = 0;
+
+   protected:
+    virtual ~Observer() {}
   };
 
   // Returns a pointer to the singleton instance of this class.