[Linux] Use PR_SET_NO_NEW_PRIVS by default in base/process/launch.h.

base/process/launch.cc

Index: base/process/launch.cc
diff --git a/base/process/launch.cc b/base/process/launch.cc
index 0c9f3a88fef2d9c8384871c6153065512717054d..81748f5f08cc2d913a4727792dc4b72c755e9a63 100644
--- a/base/process/launch.cc
+++ b/base/process/launch.cc
@@ -25,6 +25,7 @@ LaunchOptions::LaunchOptions()
       new_process_group(false)
 #if defined(OS_LINUX)
       , clone_flags(0)
+      , allow_new_privs(false)
 #endif  // OS_LINUX
 #if defined(OS_CHROMEOS)
       , ctrl_terminal_fd(-1)
@@ -36,4 +37,15 @@ LaunchOptions::LaunchOptions()
 LaunchOptions::~LaunchOptions() {
 }
 
+LaunchOptions LaunchOptionsForTest() {
+  LaunchOptions options;
+#if defined(OS_LINUX)
+  // To prevent accidental privilege sharing to an untrusted child, processes
+  // are started with PR_SET_NO_NEW_PRIVS. Do not set that here, since this
+  // new child will be used for testing only.
+  options.allow_new_privs = true;
+#endif
+  return options;
+}
+
 }  // namespace base