Adding method to create process using LowBox token in sandbox code.

sandbox/win/src/broker_services.cc

Index: sandbox/win/src/broker_services.cc
diff --git a/sandbox/win/src/broker_services.cc b/sandbox/win/src/broker_services.cc
index 8fa7f0d655168a5427287a72228c8f036c4646e4..e667e5490cd21607e5edea26b4b4a0f30cc39f09 100644
--- a/sandbox/win/src/broker_services.cc
+++ b/sandbox/win/src/broker_services.cc
@@ -410,11 +410,6 @@ ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
   bool inherit_handles = false;
   if (base::win::GetVersion() >= base::win::VERSION_VISTA) {
     int attribute_count = 0;
-    const AppContainerAttributes* app_container =
-        policy_base->GetAppContainer();
-    if (app_container)
-      ++attribute_count;
-
     DWORD64 mitigations;
     size_t mitigations_size;
     ConvertProcessMitigationsToPolicy(policy->GetProcessMitigations(),
@@ -437,12 +432,6 @@ ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
     if (!startup_info.InitializeProcThreadAttributeList(attribute_count))
       return SBOX_ERROR_PROC_THREAD_ATTRIBUTES;
 
-    if (app_container) {
-      result = app_container->ShareForStartup(&startup_info);
-      if (SBOX_ALL_OK != result)
-        return result;
-    }
-
     if (mitigations) {
       if (!startup_info.UpdateProcThreadAttribute(
                PROC_THREAD_ATTRIBUTE_MITIGATION_POLICY, &mitigations,