Disable all the browser_tests that are flaking more than 5% of the time on trybots.

chrome/browser/extensions/extension_incognito_apitest.cc

Index: chrome/browser/extensions/extension_incognito_apitest.cc
diff --git a/chrome/browser/extensions/extension_incognito_apitest.cc b/chrome/browser/extensions/extension_incognito_apitest.cc
index 06c17ca5da37b5bfbe76bc44d2149070e6a6ba79..b43833c0e69e3293c96e50106fa5337c53443665 100644
--- a/chrome/browser/extensions/extension_incognito_apitest.cc
+++ b/chrome/browser/extensions/extension_incognito_apitest.cc
@@ -120,12 +120,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTest, Incognito) {
 
 // Tests that the APIs in an incognito-enabled split-mode extension work
 // properly.
-#if defined(OS_WIN)
 // http://crbug.com/120484
 IN_PROC_BROWSER_TEST_F(ExtensionApiTest, DISABLED_IncognitoSplitMode) {
-#else
-IN_PROC_BROWSER_TEST_F(ExtensionApiTest, IncognitoSplitMode) {
-#endif
   host_resolver()->AddRule("*", "127.0.0.1");
   ASSERT_TRUE(StartEmbeddedTestServer());