Clear environment variables for nacl_helper

base/process/launch.h

 // Copyright 2013 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.
 
 // This file contains functions for launching subprocesses.
 
 #ifndef BASE_PROCESS_LAUNCH_H_
 #define BASE_PROCESS_LAUNCH_H_
 
 #include <string>
@@ skipping 70 matching lines @@
   // |inherit_handles| flag must be set to true when redirecting stdio stream.
   HANDLE stdin_handle;
   HANDLE stdout_handle;
   HANDLE stderr_handle;
 
   // If set to true, ensures that the child process is launched with the
   // CREATE_BREAKAWAY_FROM_JOB flag which allows it to breakout of the parent
   // job if any.
   bool force_breakaway_from_job_;
 #else
-  // Set/unset environment variables. Empty (the default) means to inherit
-  // the same environment. See AlterEnvironment().
+  // Set/unset environment variables. These are applied on top of the parent
+  // process environment.  Empty (the default) means to inherit the same
+  // environment. See AlterEnvironment().
   EnvironmentMap environ;
 
+  // Clear the environment for the new process before processing changes from
+  // |environ|.
+  bool clear_environ;
+
   // If non-null, remap file descriptors according to the mapping of
   // src fd->dest fd to propagate FDs into the child process.
   // This pointer is owned by the caller and must live through the
   // call to LaunchProcess().
   const FileHandleMappingVector* fds_to_remap;
 
   // Each element is an RLIMIT_* constant that should be raised to its
   // rlim_max.  This pointer is owned by the caller and must live through
   // the call to LaunchProcess().
   const std::vector<int>* maximize_rlimits;
@@ skipping 142 matching lines @@
 void RestoreDefaultExceptionHandler();
 #endif  // defined(OS_MACOSX)
 
 // Creates a LaunchOptions object suitable for launching processes in a test
 // binary. This should not be called in production/released code.
 BASE_EXPORT LaunchOptions LaunchOptionsForTest();
 
 }  // namespace base
 
 #endif  // BASE_PROCESS_LAUNCH_H_