Disable flaky PPAPINaClNewlibTest.MediaStreamAudioTrack on Mac.

chrome/test/ppapi/ppapi_browsertest.cc

Index: chrome/test/ppapi/ppapi_browsertest.cc
diff --git a/chrome/test/ppapi/ppapi_browsertest.cc b/chrome/test/ppapi/ppapi_browsertest.cc
index e8c7376f34936e4087acf80bdcab1201c71d9d11..6b671fb2e7b3180703d5674fafd5c90ca447bf17 100644
--- a/chrome/test/ppapi/ppapi_browsertest.cc
+++ b/chrome/test/ppapi/ppapi_browsertest.cc
@@ -1159,8 +1159,9 @@ IN_PROC_BROWSER_TEST_F(OutOfProcessPPAPITest, MAYBE_FlashMessageLoop) {
 TEST_PPAPI_NACL_SUBTESTS(MAYBE_Compositor0, RUN_COMPOSITOR_SUBTESTS_0)
 TEST_PPAPI_NACL_SUBTESTS(MAYBE_Compositor1, RUN_COMPOSITOR_SUBTESTS_1)
 
-#if defined(OS_LINUX) || defined(OS_WIN) || defined(OS_CHROMEOS)
-// Flaky on ChromeOS, Linux and Windows (crbug.com/438729)
+#if defined(OS_LINUX) || defined(OS_WIN) || defined(OS_CHROMEOS) || \
+    defined(OS_MACOSX)
+// Flaky on ChromeOS, Linux, Windows, and Mac (crbug.com/438729)
 #define MAYBE_MediaStreamAudioTrack DISABLED_MediaStreamAudioTrack
 #else
 #define MAYBE_MediaStreamAudioTrack MediaStreamAudioTrack