Enable IdleTimeSpellChecking in Blink Tests

third_party/WebKit/LayoutTests/TestExpectations

Index: third_party/WebKit/LayoutTests/TestExpectations
diff --git a/third_party/WebKit/LayoutTests/TestExpectations b/third_party/WebKit/LayoutTests/TestExpectations
index 752512735ed442e8b7e2e0e848b8f2fa8ab74e9a..f4c24dbcd448e4f3237203066b07e0a76338ab37 100644
--- a/third_party/WebKit/LayoutTests/TestExpectations
+++ b/third_party/WebKit/LayoutTests/TestExpectations
@@ -2473,10 +2473,5 @@ crbug.com/697342 virtual/mojo-loading/http/tests/push_messaging/permission-state
 crbug.com/698520 external/wpt/preload/fetch-destination.https.html [ Failure Pass ]
 crbug.com/698521 external/wpt/preload/preload-with-type.html [ Failure Pass ]
 
-# TODO(xiaochengh): The following tests should pass if IdleTimeSpellChecking is enabled.
-crbug.com/517298 editing/spelling/spellcheck_test.html [ Failure ]
-crbug.com/517298 editing/spelling/cold_mode_static_page.html [ Skip ]
-crbug.com/517298 editing/spelling/cold_mode_type_idle.html [ Skip ]
-
 # Sheriff failures 2017-03-06
 crbug.com/698872 [ Linux Debug ] external/wpt/service-workers/service-worker/fetch-event-redirect.https.html [ Crash ]