Re-enable NewTabUIStartupTest.PerfRefWarm on Linux. Roll to a new

chrome/test/startup/feature_startup_test.cc

Index: chrome/test/startup/feature_startup_test.cc
diff --git a/chrome/test/startup/feature_startup_test.cc b/chrome/test/startup/feature_startup_test.cc
index beb5d980c2f4f324910ba873e2413a4f21b016a8..e6aadc47b6044751c6e23dffa6bd4e249655d48a 100644
--- a/chrome/test/startup/feature_startup_test.cc
+++ b/chrome/test/startup/feature_startup_test.cc
@@ -189,10 +189,9 @@ TEST_F(NewTabUIStartupTest, PerfCold) {
                  UITest::DEFAULT_THEME);
 }
 
-#if defined(OS_WIN)
+#if !defined(OS_MACOSX)
 // TODO(tc): Update the Mac reference build to support
 // WaitForInitialNewTabUILoad.
-// TODO(tc): This is failing on Linux too.
 TEST_F(NewTabUIStartupTest, PerfRefWarm) {
   UseReferenceBuild();
   RunStartupTest("tab_warm_ref", true /* warm */, true /* not important */,