clang/win: Let some chromium_code targets build with -Wextra.

base/threading/thread_local_storage.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_THREADING_THREAD_LOCAL_STORAGE_H_
 #define BASE_THREADING_THREAD_LOCAL_STORAGE_H_
 
 #include "base/atomicops.h"
 #include "base/base_export.h"
 #include "base/basictypes.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #elif defined(OS_POSIX)
 #include <pthread.h>
 #endif
 
 namespace base {
 
 namespace internal {
 
 // WARNING: You should *NOT* be using this class directly.
 // PlatformThreadLocalStorage is low-level abstraction to the OS's TLS
 // interface, you should instead be using ThreadLocalStorage::StaticSlot/Slot.
 class BASE_EXPORT PlatformThreadLocalStorage {
  public:
 
 #if defined(OS_WIN)
   typedef unsigned long TLSKey;
-  enum { TLS_KEY_OUT_OF_INDEXES = TLS_OUT_OF_INDEXES };
+  enum : unsigned { TLS_KEY_OUT_OF_INDEXES = TLS_OUT_OF_INDEXES };
 #elif defined(OS_POSIX)
   typedef pthread_key_t TLSKey;
   // The following is a "reserved key" which is used in our generic Chromium
   // ThreadLocalStorage implementation.  We expect that an OS will not return
   // such a key, but if it is returned (i.e., the OS tries to allocate it) we
   // will just request another key.
   enum { TLS_KEY_OUT_OF_INDEXES = 0x7FFFFFFF };
 #endif
 
   // The following methods need to be supported on each OS platform, so that
@@ skipping 97 matching lines @@
     DISALLOW_COPY_AND_ASSIGN(Slot);
   };
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ThreadLocalStorage);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_THREAD_LOCAL_STORAGE_H_