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

chrome/browser/chrome_main_browsertest.cc

Index: chrome/browser/chrome_main_browsertest.cc
diff --git a/chrome/browser/chrome_main_browsertest.cc b/chrome/browser/chrome_main_browsertest.cc
index 30bcf7156c9e7fddd1c0cc3db0e5d301ce2ae4b0..05faa67f82c58d75b8cb7810de54f56317399b25 100644
--- a/chrome/browser/chrome_main_browsertest.cc
+++ b/chrome/browser/chrome_main_browsertest.cc
@@ -32,7 +32,14 @@ class ChromeMainTest : public InProcessBrowserTest {
   ChromeMainTest() {}
 
   void Relaunch(const CommandLine& new_command_line) {
-    base::LaunchProcess(new_command_line, base::LaunchOptions(), NULL);
+    base::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 a test browser process.
+    options.allow_new_privs = true;
+#endif
+    base::LaunchProcess(new_command_line, options, NULL);
   }
 };