Disable the externally connectable tests on windows.

chrome/browser/extensions/extension_messages_apitest.cc

Index: chrome/browser/extensions/extension_messages_apitest.cc
diff --git a/chrome/browser/extensions/extension_messages_apitest.cc b/chrome/browser/extensions/extension_messages_apitest.cc
index 593a73f1ed4dd940b65e35b34d1d3bc9d1f4ac36..36e2f383686c708540371d87b51ea6392b38b70a 100644
--- a/chrome/browser/extensions/extension_messages_apitest.cc
+++ b/chrome/browser/extensions/extension_messages_apitest.cc
@@ -134,6 +134,10 @@ IN_PROC_BROWSER_TEST_F(PanelMessagingTest, MessagingPanel) {
   ASSERT_TRUE(RunExtensionTest("messaging/connect_panel")) << message_;
 }
 
+// XXX(kalman): All web messaging tests disabled on windows due to extreme
+// flakiness. See http://crbug.com/350517.
+#if !defined(OS_WIN)
+
 // Tests externally_connectable between a web page and an extension.
 //
 // TODO(kalman): Test between extensions. This is already tested in this file,
@@ -953,6 +957,8 @@ IN_PROC_BROWSER_TEST_F(ExternallyConnectableMessagingTest,
             CanConnectAndSendMessages("invalid"));
 }
 
+#endif  // !defined(OS_WIN) - http://crbug.com/350517.
+
 }  // namespace
 
 };  // namespace extensions