Disable more layout tests after r548309

The tests are failing consistently on chromium.webkit/WebKit Mac10.10.

TBR=thomasanderson@chromium.org

Bug: 787020,829282
Change-Id: Ibad916df060e441b99cb13b8970ce85c1f34bec0
Reviewed-on: https://chromium-review.googlesource.com/997555Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548384}

third_party/WebKit/LayoutTests/TestExpectations

@@ -4001,6 +4001,10 @@ crbug.com/785955 http/tests/credentialmanager/tools/virtual-authenticator-enviro
 # Disabled after r548309.  TODO(thomasanderson): Reenable these tests
 crbug.com/787020 virtual/gpu/fast/canvas/canvas-zero-length-lineCap.html [ Pass Failure ]
 crbug.com/787020 virtual/threaded/http/tests/devtools/tracing/timeline-js/compile-script.js [ Pass Failure ]
+crbug.com/787020 external/wpt/service-workers/service-worker/ServiceWorkerGlobalScope/extendable-message-event.https.html [ Pass Failure ]
+crbug.com/787020 external/wpt/shadow-dom/untriaged/events/retargeting-focus-events/test-003.html [ Pass Failure ]
+crbug.com/787020 virtual/incremental-shadow-dom/external/wpt/shadow-dom/untriaged/events/retargeting-focus-events/test-003.html [ Pass Failure ]
+crbug.com/787020 virtual/navigation-mojo-response/external/wpt/service-workers/service-worker/ServiceWorkerGlobalScope/extendable-message-event.https.html [ Pass Failure ]
 
 # These Web Authentication API would require either real hardware, or
 # virtual simulation thereof (work in progress, see: https://crbug.com/785955).