Remove task.h and finish base::Bind() migration.

base/at_exit.cc

 // 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.
 
 #include "base/at_exit.h"
 
 #include <stddef.h>
 #include <ostream>
 
 #include "base/bind.h"
+#include "base/callback.h"
 #include "base/logging.h"
-#include "base/task.h"
 
 namespace base {
 
 // Keep a stack of registered AtExitManagers.  We always operate on the most
 // recent, and we should never have more than one outside of testing (for a
 // statically linked version of this library).  Testing may use the shadow
 // version of the constructor, and if we are building a dynamic library we may
 // end up with multiple AtExitManagers on the same process.  We don't protect
 // this for thread-safe access, since it will only be modified in testing.
 static AtExitManager* g_top_manager = NULL;
@@ skipping 50 matching lines @@
     g_top_manager->stack_.pop();
   }
 }
 
 AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
   DCHECK(shadow || !g_top_manager);
   g_top_manager = this;
 }
 
 }  // namespace base