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

chrome/test/nacl/nacl_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdio.h>
 #if defined(OS_POSIX)
 #include <unistd.h>
 #elif defined(OS_WIN)
 #include <windows.h>
 #endif
@@ skipping 426 matching lines @@
   RunNaClIntegrationTest(FILE_PATH_LITERAL(
       "pm_redir_test.html?stream=stderr&thread=fg&delay_us=1000000"));
 }
 
 IN_PROC_BROWSER_TEST_F(NaClBrowserTestNewlibStderrPM, RedirectBg1) {
   RunNaClIntegrationTest(FILE_PATH_LITERAL(
       "pm_redir_test.html?stream=stderr&thread=bg&delay_us=1000000"));
 }
 
 // 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"));
 }
 
 }  // namespace