Let WeakPtrFactory operations fail once its dtor is called

base/memory/weak_ptr.h

Index: base/memory/weak_ptr.h
diff --git a/base/memory/weak_ptr.h b/base/memory/weak_ptr.h
index b66f02431aac2aa48bcf9babc396de3d8e055095..f7bf677f1aac2886f569863265413989a1de0ce8 100644
--- a/base/memory/weak_ptr.h
+++ b/base/memory/weak_ptr.h
@@ -231,23 +231,30 @@ class WeakPtrFactory {
  public:
   explicit WeakPtrFactory(T* ptr) : ptr_(ptr) {
   }
+  ~WeakPtrFactory(){

[darin (slow to review), 2012/05/17 22:00:52]

nit: add new line above the destructor

[oshima, 2012/05/17 22:16:43]

Done.

+    ptr_ = NULL;

[darin (slow to review), 2012/05/17 22:00:52]

i wonder... should we null this out only in debug builds?

[oshima, 2012/05/17 22:16:43]

I wanted this to fail on trybots, which is release build but
dcheck enabled. How about this then?

#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)

+  }
 
   WeakPtr<T> GetWeakPtr() {
+    DCHECK(ptr_);
     return WeakPtr<T>(weak_reference_owner_.GetRef(), ptr_);
   }
 
   // Call this method to invalidate all existing weak pointers.
   void InvalidateWeakPtrs() {
+    DCHECK(ptr_);
     weak_reference_owner_.Invalidate();
   }
 
   // Call this method to determine if any weak pointers exist.
   bool HasWeakPtrs() const {
+    DCHECK(ptr_);
     return weak_reference_owner_.HasRefs();
   }
 
   // Indicates that this object will be used on another thread from now on.
   void DetachFromThread() {
+    DCHECK(ptr_);
     weak_reference_owner_.DetachFromThread();
   }