Rewrite most of the scopers in //base/mac to use ScopedTypeRef or ScopedGeneric.

base/mac/scoped_cftyperef.h

Index: base/mac/scoped_cftyperef.h
diff --git a/base/mac/scoped_cftyperef.h b/base/mac/scoped_cftyperef.h
index 3a77da15f5605cfb1eb0ebcf21e20e10f5baebb2..1be0fbe56d1e1002f2c96b71c550a9b28b0b505e 100644
--- a/base/mac/scoped_cftyperef.h
+++ b/base/mac/scoped_cftyperef.h
@@ -30,8 +30,9 @@ namespace internal {
 template<typename CFT>
 struct ScopedCFTypeRefTraits {
   static CFT InvalidValue() { return nullptr; }
-  static void Retain(CFT object) {
+  static CFT Retain(CFT object) {
     CFRetain(object);
+    return object;
   }
   static void Release(CFT object) {
     CFRelease(object);