Disable ServiceWorkerBasedBackgroundTest.Basic due to flakes.

BUG=855800
TBR=lazyboy@chromium.org
NOTRY=true

Change-Id: I5eb0663724303fd7f7f2eb4b0feac36c82cc4421
Reviewed-on: https://chromium-review.googlesource.com/1116796Reviewed-by: Greg Thompson <grt@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570739}

chrome/browser/extensions/service_worker_apitest.cc

@@ -287,11 +287,17 @@ IN_PROC_BROWSER_TEST_P(ServiceWorkerBasedBackgroundTest, PRE_Basic) {
   EXPECT_FALSE(process_manager()->GetBackgroundHostForExtension(extension_id));
 }
 
+#if defined(OS_LINUX)
+// Disabled on Linux due to flakes; see https://crbug.com/855800.
+#define MAYBE_Basic DISABLED_Basic
+#else
+#define MAYBE_Basic Basic
+#endif
 // After browser restarts, this test step ensures that opening a tab fires
 // tabs.onCreated event listener to the extension without explicitly loading the
 // extension. This is because the extension registered a listener before browser
 // restarted in PRE_Basic.
-IN_PROC_BROWSER_TEST_P(ServiceWorkerBasedBackgroundTest, Basic) {
+IN_PROC_BROWSER_TEST_P(ServiceWorkerBasedBackgroundTest, MAYBE_Basic) {
   ExtensionTestMessageListener newtab_listener("CREATED", false);
   newtab_listener.set_failure_message("CREATE_FAILED");
   const GURL url = embedded_test_server()->GetURL("/extensions/test_file.html");