Style cleanup in preparation for auto-linting base/.

base/at_exit.h

 // Copyright (c) 2006-2008 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_AT_EXIT_H_
 #define BASE_AT_EXIT_H_
 
 #include <stack>
 
 #include "base/basictypes.h"
@@ skipping 14 matching lines @@
 // }
 // When the exit_manager object goes out of scope, all the registered
 // callbacks and singleton destructors will be called.
 
 class AtExitManager {
  protected:
   // This constructor will allow this instance of AtExitManager to be created
   // even if one already exists.  This should only be used for testing!
   // AtExitManagers are kept on a global stack, and it will be removed during
   // destruction.  This allows you to shadow another AtExitManager.
-  AtExitManager(bool shadow);
+  explicit AtExitManager(bool shadow);
 
  public:
   typedef void (*AtExitCallbackType)(void*);
 
   AtExitManager();
 
   // The dtor calls all the registered callbacks. Do not try to register more
   // callbacks after this point.
   ~AtExitManager();
 
@@ skipping 23 matching lines @@
 #if defined(UNIT_TEST)
 class ShadowingAtExitManager : public AtExitManager {
  public:
   ShadowingAtExitManager() : AtExitManager(true) {}
 };
 #endif  // defined(UNIT_TEST)
 
 }  // namespace base
 
 #endif  // BASE_AT_EXIT_H_