Fix a misuse of pragma disable/default in a header file.

base/bind_helpers.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This defines a set of argument wrappers and related factory methods that
 // can be used specify the refcounting and reference semantics of arguments
 // that are bound by the Bind() function in base/bind.h.
 //
 // It also defines a set of simple functions and utilities that people want
 // when using Callback<> and Bind().
@@ skipping 219 matching lines @@
   typedef char No[2];
 
   struct BaseMixin {
     void AddRef();
   };
 
 // MSVC warns when you try to use Base if T has a private destructor, the
 // common pattern for refcounted types. It does this even though no attempt to
 // instantiate Base is made.  We disable the warning for this definition.
 #if defined(OS_WIN)
+#pragma warning(push)
 #pragma warning(disable:4624)
 #endif
   struct Base : public T, public BaseMixin {
   };
 #if defined(OS_WIN)
-#pragma warning(default:4624)
+#pragma warning(pop)

[erikwright (departed), 2013/07/26 15:17:56]

One could just pull the push outside of the #if defined and then remove the #if
defined around the pop.

But I'd let Albert indicate which he prefers.

[awong, 2013/07/26 17:50:09]

I'm confused...don't the pragmas need to be inside the if defined always?

Anyways, looks good as is.

 #endif
 
   template <void(BaseMixin::*)(void)> struct Helper {};
 
   template <typename C>
   static No& Check(Helper<&C::AddRef>*);
 
   template <typename >
   static Yes& Check(...);
 
@@ skipping 297 matching lines @@
 
  private:
   Closure closure_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(ScopedClosureRunner);
 };
 
 }  // namespace base
 
 #endif  // BASE_BIND_HELPERS_H_