Enable WebNavigationApiTest.Failures on Windows and Mac.

Bug: 477840, 746407
Change-Id: Id10d8f38903bf64c67d0a8ca8dc0f09142907355
Reviewed-on: https://chromium-review.googlesource.com/600949
Commit-Queue: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491837}

chrome/browser/extensions/api/web_navigation/web_navigation_apitest.cc

@@ -486,14 +486,7 @@ IN_PROC_BROWSER_TEST_F(WebNavigationApiTest, SimpleLoad) {
   ASSERT_TRUE(RunExtensionTest("webnavigation/simpleLoad")) << message_;
 }
 
-// Flaky on Windows and Mac. See http://crbug.com/477480 (Windows) and
-// https://crbug.com/746407 (Mac).
-#if defined(OS_WIN) || defined(OS_MACOSX)
-#define MAYBE_Failures DISABLED_Failures
-#else
-#define MAYBE_Failures Failures
-#endif
-IN_PROC_BROWSER_TEST_F(WebNavigationApiTest, MAYBE_Failures) {
+IN_PROC_BROWSER_TEST_F(WebNavigationApiTest, Failures) {
   ASSERT_TRUE(StartEmbeddedTestServer());
   ASSERT_TRUE(RunExtensionTest("webnavigation/failures")) << message_;
 }