Revert of Revert of [ServivceWorker] Treat rejecting respondWith as a Network Error (patchset #1 id:1 of https://codereview.chromium.org/580993002/)

Reason for revert:
Landed the patch to initialize WebServiceWorkerResponse's status.

https://codereview.chromium.org/575153002/

Original issue's description:
> Revert of [ServivceWorker] Treat rejecting respondWith as a Network Error (patchset #4 id:60001 of https://codereview.chromium.org/571843003/)
> 
> Reason for revert:
> WebServiceWorkerResponse's status is not initialised.
> This may cause problems.
> 
> I will re-land this patch after https://codereview.chromium.org/575153002/ is submitted.
> 
> Original issue's description:
> > [ServivceWorker] Treat rejecting respondWith as a Network Error
> > 
> > Chromium side change is this: https://codereview.chromium.org/574643003/
> > 
> > 
> > BUG=411173
> > TEST=layouttest http/tests/serviceworker/
> > 
> > Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182147
> 
> TBR=yhirano@chromium.org,mkwst@chromium.org,tkent@chromium.org,nhiroki@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=411173
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182204

TBR=yhirano@chromium.org,mkwst@chromium.org,tkent@chromium.org,nhiroki@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=411173

Review URL: https://codereview.chromium.org/585733002

git-svn-id: svn://svn.chromium.org/blink/trunk@182290 bbb929c8-8fbe-4397-9dbb-9b2b20218538