Mark ExtensionApiTest.WindowOpen as flaky

BUG=477691
NOTRY=true
NOTREECHECKS=true
TBR=stevenjb@chromium.org

Review URL: https://codereview.chromium.org/1059963005

Cr-Commit-Position: refs/heads/master@{#325443}

chrome/browser/extensions/window_open_apitest.cc

@@ -49,12 +49,8 @@ using content::WebContents;
 // The test uses the chrome.browserAction.openPopup API, which requires that the
 // window can automatically be activated.
 // See comments at BrowserActionInteractiveTest::ShouldRunPopupTest
-#if defined(OS_MACOSX)
-#define MAYBE_WindowOpen DISABLED_WindowOpen
-#else
-#define MAYBE_WindowOpen WindowOpen
-#endif
-IN_PROC_BROWSER_TEST_F(ExtensionApiTest, MAYBE_WindowOpen) {
+// Fails flakily on all platforms. https://crbug.com/477691
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, DISABLED_WindowOpen) {
   extensions::ResultCatcher catcher;
   ASSERT_TRUE(LoadExtensionIncognito(test_data_dir_
       .AppendASCII("window_open").AppendASCII("spanning")));