Revert of [XMLHttpRequest] Stop throwing for network error in async mode

Revert of [XMLHttpRequest] Stop throwing for network error in async mode (patchset #8 id:140001 of https://codereview.chromium.org/1060113004/)

Reason for revert:
The test is causing browser_tests
ExtensionApiTest.CrossOriginXHRNoFileAccess to fail on the Linux Chromium OS and the gn bots. Manually confirmed that it's the culprit with a gn component build on Linux.

Relevant log:
[FAIL] fileAccessNotAllowed: expected an error to be thrown
Error
    at fileAccessNotAllowed
(chrome-extension://dgmgifjgehkiibkkonbjcmcnagdegeco/test.js:24:21)
    at Object.\u003Canonymous> (extensions::test:95:19)
    at Object.handleRequest (extensions::binding:57:27)
    at Object.\u003Canonymous> (extensions::binding:385:32)
    at Object.\u003Canonymous> (extensions::test:326:16)
    at Object.handleRequest (extensions::binding:57:27)
    at Object.\u003Canonymous> (extensions::binding:385:32)
    at Object.callback
(chrome-extension://dgmgifjgehkiibkkonbjcmcnagdegeco/test.js:6:15)
    at safeCallbackApply (extensions::sendRequest:21:15)
    at handleResponse (extensions::sendRequest:72:7)", source:
chrome-extension://dgmgifjgehkiibkkonbjcmcnagdegeco/test.html (0)
../../chrome/browser/extensions/cross_origin_xhr_apitest.cc:37: Failure
Value of: RunExtensionTestNoFileAccess( "cross_origin_xhr/no_file_access")
  Actual: false
Expected: true

Full log of the failure:
https://build.chromium.org/p/chromium.webkit/builders/Linux%20ChromiumOS%20Tests%20%281%29/builds/17039/steps/browser_tests/logs/ExtensionApiTest.CrossOriginXHRNoFileAccess.

Original issue's description:
> [XMLHttpRequest] Stop throwing for network error in async mode
> 
> See the history and decision at http://crbug.com/479484
> 
> This CL updates fast/files/apply-blob-url-to-xhr.html layout test to
> stop expecting an exception but expect an error event being
> dispatched. Using this opportunity, merged the worker version of the
> test into one test script.
> 
> security/cannot-read-self-from-file and
> http/tests/xmlhttprequest/cross-origin-unsupported-url (and its worker
> version) are simply updated to expect error event dispatching.
> 
> BUG=479484
> R=sof,mkwst
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199098

TBR=mkwst@chromium.org,sigbjornf@opera.com,tyoshino@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=479484
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199120

[Julien - ping for review, 2015-07-17 17:34:18]

Created Revert of [XMLHttpRequest] Stop throwing for network error in async mode

[commit-bot: I haz the power, 2015-07-17 17:35:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1240503004/1

[commit-bot: I haz the power, 2015-07-17 17:36:03]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199120