Disable all the tests that are flaking more than 5% on Windows builders.

chrome/test/nacl/nacl_browsertest.cc

Index: chrome/test/nacl/nacl_browsertest.cc
diff --git a/chrome/test/nacl/nacl_browsertest.cc b/chrome/test/nacl/nacl_browsertest.cc
index 377640d460a869e63331c545dd0ac7681169a007..d95cc36579e895894236f33845a3b58199e8df6a 100644
--- a/chrome/test/nacl/nacl_browsertest.cc
+++ b/chrome/test/nacl/nacl_browsertest.cc
@@ -444,13 +444,8 @@ IN_PROC_BROWSER_TEST_F(NaClBrowserTestNewlibStderrPM, RedirectBg1) {
 }
 
 // TODO(ncbray) support glibc and PNaCl
-#if defined(OS_MACOSX)
-// crbug.com/375894
-#define MAYBE_MimeHandler DISABLED_MimeHandler
-#else
-#define MAYBE_MimeHandler MimeHandler
-#endif
-IN_PROC_BROWSER_TEST_F(NaClBrowserTestNewlibExtension, MAYBE_MimeHandler) {
+// flaky: crbug.com/375894
+IN_PROC_BROWSER_TEST_F(NaClBrowserTestNewlibExtension, DISABLED_MimeHandler) {
   RunNaClIntegrationTest(FILE_PATH_LITERAL(
       "ppapi_extension_mime_handler.html"));
 }