service worker: Fix WPT test fetch-frame-resource.https.html

There were two issues:
* The contentWindow access was throwing an exception because Chrome's
error pages are considered cross-origin.
* The test uses a setTimeout of 10 sec since Mozilla had flaky failures at 5
sec. This issue is still unresolved, see github.com/w3c/ServiceWorker/issues/1194
However, somehow the test seems to pass on local Release despite taking over
6 seconds, so I'm leaving it out of SlowTests for now.

Bug: 758892
Change-Id: I4ff501bcc679db6e7d6ddd7d70adfd33e79bd718
Reviewed-on: https://chromium-review.googlesource.com/664460
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501575}

third_party/WebKit/LayoutTests/TestExpectations

@@ -2411,11 +2411,6 @@ crbug.com/508728 external/wpt/workers/Worker_cross_origin_security_err.htm [ Tim
 # This test needs to be updated: fails because it expects showModalDialog and some other APIs.
 crbug.com/508728 external/wpt/html/browsers/the-window-object/security-window/window-security.html [ Failure ]
 
-crbug.com/602693 external/wpt/service-workers/service-worker/fetch-frame-resource.https.html [ Timeout ]
-crbug.com/602693 virtual/service-worker-script-streaming/external/wpt/service-workers/service-worker/fetch-frame-resource.https.html [ Timeout ]
-crbug.com/602693 virtual/mojo-blobs/external/wpt/service-workers/service-worker/fetch-frame-resource.https.html [ Timeout ]
-crbug.com/602693 virtual/outofblink-cors/external/wpt/service-workers/service-worker/fetch-frame-resource.https.html [ Timeout ]
-
 # This test requires a special browser flag and seems not suitable for a wpt test, see bug.
 crbug.com/691944 external/wpt/service-workers/service-worker/update-after-oneday.https.html [ Skip ]
 crbug.com/691944 virtual/service-worker-script-streaming/external/wpt/service-workers/service-worker/update-after-oneday.https.html [ Skip ]

third_party/WebKit/LayoutTests/external/wpt/service-workers/service-worker/fetch-frame-resource.https.html

@@ -50,7 +50,12 @@ function getLoadedObject(win, contentFunc, closeFunc) {
 
       win.onload = function() {
           clearTimeout(timeout);
-          var content = contentFunc(win);
+          let content = '';
+          try {
+            content = contentFunc(win);
+          } catch(e) {
+            // use default empty string for cross-domain window (see above)
+          }
           done(content);
         };
     });