Moving ProfileDestroyer from ref counting to WeakPtr.

chrome/browser/profiles/profile_destroyer.h

Index: chrome/browser/profiles/profile_destroyer.h
diff --git a/chrome/browser/profiles/profile_destroyer.h b/chrome/browser/profiles/profile_destroyer.h
index 62aa7c1348bc28552763d373b719dd035eae740e..70a4752420d353cd31cf56af1949e5249ee85cf7 100644
--- a/chrome/browser/profiles/profile_destroyer.h
+++ b/chrome/browser/profiles/profile_destroyer.h
@@ -20,8 +20,7 @@ class RenderProcessHost;
 // We use this class to destroy the off the record profile so that we can make
 // sure it gets done asynchronously after all render process hosts are gone.
 class ProfileDestroyer
-    : public content::NotificationObserver,
-      public base::RefCounted<ProfileDestroyer> {
+    : public content::NotificationObserver {
  public:
   static void DestroyProfileWhenAppropriate(Profile* const profile);
   static void DestroyOffTheRecordProfileNow(Profile* const profile);
@@ -61,6 +60,8 @@ class ProfileDestroyer
 
   Profile* profile_;
 
+  base::WeakPtrFactory<ProfileDestroyer> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileDestroyer);
 };