Improve scoped_cftyperef<> and scoped_nsobject<> reset() semantics.

base/scoped_cftyperef.h

Index: base/scoped_cftyperef.h
===================================================================
--- base/scoped_cftyperef.h	(revision 12287)
+++ base/scoped_cftyperef.h	(working copy)
@@ -15,7 +15,9 @@
 //
 // When scoped_cftyperef<> takes ownership of an object (in the constructor or
 // in reset()), it takes over the caller's existing ownership claim.  The 
-// caller must own the object.  scoped_cftyperef<> does not call CFRetain().
+// caller must own the object it gives to scoped_cftyperef<>, and relinquishes
+// an ownership claim to that object.  scoped_cftyperef<> does not call
+// CFRetain().
 template<typename CFT>
 class scoped_cftyperef {
  public:
@@ -31,11 +33,9 @@
   }
 
   void reset(CFT object = NULL) {
-    if (object_ != object) {
-      if (object_)
-        CFRelease(object_);
-      object_ = object;
-    }
+    if (object_)

[TVL, 2009/03/23 17:30:22]

part of me thinks it's better to match the other scoped_* helpers so they are
all alike.  the downside, here is w/o the equality check, if someone updated
this w/o checking for equality, it could store a stale pointer since it will
dump the object and then keep the ptr again.

+      CFRelease(object_);
+    object_ = object;
   }
 
   bool operator==(CFT that) const {