Allow using the namespace sandbox in zygote host.

sandbox/linux/services/namespace_sandbox.h

Index: sandbox/linux/services/namespace_sandbox.h
diff --git a/sandbox/linux/services/namespace_sandbox.h b/sandbox/linux/services/namespace_sandbox.h
index ddc4deefc4fc9bed3e2bc5a72f60d6aef29a8028..b92f5818f1bee1b4afb3cc32e260113dd6caa48b 100644
--- a/sandbox/linux/services/namespace_sandbox.h
+++ b/sandbox/linux/services/namespace_sandbox.h
@@ -5,6 +5,9 @@
 #ifndef SANDBOX_LINUX_SERVICES_NAMESPACE_SANDBOX_H_
 #define SANDBOX_LINUX_SERVICES_NAMESPACE_SANDBOX_H_
 
+#include <string>
+#include <vector>
+
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/process/launch.h"
@@ -41,6 +44,8 @@ class SANDBOX_EXPORT NamespaceSandbox {
   // overrides them.
   static base::Process LaunchProcess(const base::CommandLine& cmdline,
                                      const base::LaunchOptions& options);
+  static base::Process LaunchProcess(const std::vector<std::string>& argv,
+                                     const base::LaunchOptions& options);
 
   // Returns whether the namespace sandbox created a new user, PID, and network
   // namespace. In particular, InNewUserNamespace should return true iff the