Mark networkState_during_progress.html flaky

This test was made flaky by this CL:
  https://chromium-review.googlesource.com/c/chromium/src/+/1213864

TBR=masonfreed@chromium.org
NOTRY=true

Bug: 903019
Change-Id: Ifd936eb36d2a2731a66f391c54de5ec019963d5e
Reviewed-on: https://chromium-review.googlesource.com/c/1330216Reviewed-by: Mason Freed <masonfreed@chromium.org>
Commit-Queue: Mason Freed <masonfreed@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606944}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1851,8 +1851,8 @@ crbug.com/492664 [ Win ] external/wpt/css/css-writing-modes/bidi-plaintext-001.h
 crbug.com/280342 [ Mac Linux Win ] http/tests/media/progress-events-generated-correctly.html [ Failure Pass ]
 
 crbug.com/520736 [ Win7 Linux ] media/W3C/video/networkState/networkState_during_progress.html [ Failure Pass ]
-crbug.com/520736 [ Win7 Mac ] virtual/video-surface-layer/media/W3C/video/networkState/networkState_during_progress.html [ Failure Pass ]
-
+# This is also flaky from findit, see crbug.com/903019:
+crbug.com/520736 virtual/video-surface-layer/media/W3C/video/networkState/networkState_during_progress.html [ Pass Failure Timeout Crash ]
 crbug.com/865839 external/wpt/service-workers/service-worker/update-after-navigation-redirect.https.html [ Timeout ]
 
 crbug.com/841922 [ Linux Win Mac ] virtual/video-surface-layer/media/video-controls-focus-movement-on-hide.html [ Pass Failure ]