Rewrite scoped_ptr<T>(NULL) to use the default ctor.

tools/android/forwarder2/daemon.cc

 // 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.
 
 #include "tools/android/forwarder2/daemon.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <sys/file.h>
@@ skipping 133 matching lines @@
     if (socket->Read(buf, sizeof(buf)) < 0) {
       perror("read");
       continue;
     }
     if (expected_welcome_message != buf) {
       LOG(ERROR) << "Unexpected message read from daemon: " << buf;
       break;
     }
     return socket.Pass();
   }
-  return scoped_ptr<Socket>(NULL);
+  return scoped_ptr<Socket>();
 }
 
 }  // namespace
 
 Daemon::Daemon(const std::string& log_file_path,
                const std::string& identifier,
                ClientDelegate* client_delegate,
                ServerDelegate* server_delegate,
                GetExitNotifierFDCallback get_exit_fd_callback)
   : log_file_path_(log_file_path),
@@ skipping 115 matching lines @@
       return true;
     }
     usleep(kIdleTimeMSec * 1000);
   }
   LOG(ERROR) << "Timed out while killing daemon. "
                 "It might still be tearing down.";
   return false;
 }
 
 }  // namespace forwarder2