Add a switch for using PNaCl Subzero and use it for -O0 translation.

chrome/test/nacl/nacl_browsertest_util.cc

Index: chrome/test/nacl/nacl_browsertest_util.cc
diff --git a/chrome/test/nacl/nacl_browsertest_util.cc b/chrome/test/nacl/nacl_browsertest_util.cc
index f1e0f805a5ff0c3fa597c3e8e60b2d0c154efec9..996efe26b4a0ffbdf8a1770f81f669b1c2a180d1 100644
--- a/chrome/test/nacl/nacl_browsertest_util.cc
+++ b/chrome/test/nacl/nacl_browsertest_util.cc
@@ -283,6 +283,12 @@ bool NaClBrowserTestPnacl::IsAPnaclTest() {
   return true;
 }
 
+void NaClBrowserTestPnaclSubzero::SetUpCommandLine(
+    base::CommandLine* command_line) {
+  NaClBrowserTestPnacl::SetUpCommandLine(command_line);
+  command_line->AppendSwitch(switches::kEnablePNaClSubzero);
+}
+
 base::FilePath::StringType NaClBrowserTestNonSfiMode::Variant() {
   return FILE_PATH_LITERAL("libc-free");
 }