It seems that we are expecting the test to fail, but it actually passed.

Output is:

```
--- /b/s/w/ioocUbfe/layout-test-results/external/wpt/html/semantics/text-level-semantics/the-a-element/a-download-click-404-expected.txt
+++ /b/s/w/ioocUbfe/layout-test-results/external/wpt/html/semantics/text-level-semantics/the-a-element/a-download-click-404-actual.txt
@@ -1,4 +1,4 @@
 This is a testharness.js-based test.
-FAIL Do not navigate to 404 for anchor with download Blocked a frame with origin "http://web-platform.test:8001" from accessing a cross-origin frame.
+PASS Do not navigate to 404 for anchor with download
 Harness: the test ran to completion.
```

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/990eaa62cd17d61ed0178fac39581a01b72ee649

commit 990eaa62cd17d61ed0178fac39581a01b72ee649
Author: Chong Zhang <chongz@chromium.org>
Date: Mon Feb 26 20:19:57 2018

NetworkService sheriff: update layout test expectation

external/wpt/html/semantics/text-level-semantics/the-a-element/a-download-click-404.html
regressed after the change in bug.

TBR=jochen@chromium.org

Bug:  816556 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: Ic8e15dbe0c629dcbb3f35859cb614525a1427683
Reviewed-on: https://chromium-review.googlesource.com/937903
Commit-Queue: Chong Zhang <chongz@chromium.org>
Reviewed-by: Chong Zhang <chongz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539251}
[modify] https://crrev.com/990eaa62cd17d61ed0178fac39581a01b72ee649/third_party/WebKit/LayoutTests/FlagExpectations/enable-features=NetworkService

well, it passes, right?

guess we can just remove the failing expectation once network service launches..

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5e41909c8652d63ac4f3d408f4b47eaa7a5f028f

commit 5e41909c8652d63ac4f3d408f4b47eaa7a5f028f
Author: John Abd-El-Malek <jam@chromium.org>
Date: Thu Apr 26 20:07:09 2018

Enable some download related layout tests with network service.

These are passing.

Bug:  816556 ,  829721 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I711c4a0739cabd7f6a4a10338d8c2c1a755a693c
Reviewed-on: https://chromium-review.googlesource.com/1028999
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554125}
[modify] https://crrev.com/5e41909c8652d63ac4f3d408f4b47eaa7a5f028f/third_party/WebKit/LayoutTests/FlagExpectations/enable-features=NetworkService