Clear environment variables for nacl_helper

base/process/launch.h

Index: base/process/launch.h
diff --git a/base/process/launch.h b/base/process/launch.h
index 9e39fba6297d92bfcaae23dd89b439c187e99156..bcd643736eecf30471cc6f465ee0a2650b6ee7c6 100644
--- a/base/process/launch.h
+++ b/base/process/launch.h
@@ -92,6 +92,10 @@ struct BASE_EXPORT LaunchOptions {
   // 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