Reland of Shows error messages in the inspector when .respondWith() is called with wrong responses.

Reland of Shows error messages in the inspector when .respondWith() is called with wrong responses. (patchset #1 id:1 of https://codereview.chromium.org/1252443003/)

Reason for revert:
Temporarily disabled the falling test (ServiceWorkerVersionBrowserTest.FetchEvent_respondWithRejection)
https://crrev.com/1254523002

https://codereview.chromium.org/1252503006/ will update the test expectation.


Original issue's description:
> Revert of Shows error messages in the inspector when .respondWith() is called with wrong responses. (patchset #4 id:100001 of https://codereview.chromium.org/1228233007/)
> 
> Reason for revert:
> Causes content_browsertests failures: http://build.chromium.org/p/chromium.webkit/builders/Linux%20Tests/builds/45600
> 
> Original issue's description:
> > Shows error messages in the inspector when .respondWith() is called with wrong responses.
> > 
> > To let the developer know about the reason of the failure.
> > 
> > BUG=505784
> > 
> > Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199287
> 
> TBR=mkwst@chromium.org,falken@chromium.org,horo@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=505784
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199298

TBR=mkwst@chromium.org,falken@chromium.org,yhirano@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=505784
Committed: https://crrev.com/43af0956af83dd67b11ed3364d63453d68304f96
git-svn-id: svn://svn.chromium.org/blink/trunk@199413 bbb929c8-8fbe-4397-9dbb-9b2b20218538

[horo, 2015-07-24 01:53:47]

Created Reland of Shows error messages in the inspector when .respondWith() is
called with wrong responses.

[commit-bot: I haz the power, 2015-07-24 03:54:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1250363002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1250363002/1

[commit-bot: I haz the power, 2015-07-24 03:56:27]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199413

[commit-bot: I haz the power, 2015-09-23 11:45:25]

Patchset 1 (id:??) landed as
https://crrev.com/43af0956af83dd67b11ed3364d63453d68304f96