Fix a bunch of IWYU violators that don't include scoped_ptr.h

tools/gn/exec_process.cc

 // Copyright 2014 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/gn/exec_process.h"
 
 #include <stddef.h>
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/process/process.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 
 #include "base/win/scoped_handle.h"
 #include "base/win/scoped_process_information.h"
@@ skipping 227 matching lines @@
         return process.WaitForExit(exit_code);
       }
   }
 
   return false;
 }
 #endif
 
 }  // namespace internal