WebCore::ResourceErrorBase::setType is crashing
https://bugs.webkit.org/show_bug.cgi?id=162484
<rdar://problem/28390828>

Patch by Youenn Fablet <youenn@apple.com> on 2016-09-28
Reviewed by Alex Christensen.

Source/WebCore:

Test: http/tests/xmlhttprequest/on-network-timeout-error-during-preflight.html

Behavior is slightly changed as we are no longer casting Timeout preflight errors as AccessControl errors.
This is more inline with fetch spec which prescribes to send back any error received by preflight as response error for fetch.

Ideally, we should not need to change errors received during preflight loads but the error type is important for some clients:
- EventSource may try to reconnect if error is not AccessControl
- XMLHttpRequest will send abort events in case of Cancellation errors and timeout events in case of Timeout errors

* loader/CrossOriginPreflightChecker.cpp:
(WebCore::CrossOriginPreflightChecker::notifyFinished): Setting error type to AccessControl except in case of Timeout.
(WebCore::CrossOriginPreflightChecker::doPreflight): Ditto.
* loader/DocumentThreadableLoader.cpp:
(WebCore::DocumentThreadableLoader::preflightFailure): Removing ASSERT since Timeout errors may be returned.
* platform/network/ResourceErrorBase.h:
(WebCore::ResourceErrorBase::isGeneral): New getter.

LayoutTests:

* http/tests/xmlhttprequest/on-network-timeout-error-during-preflight-expected.txt: Added.
* http/tests/xmlhttprequest/on-network-timeout-error-during-preflight.html: Added.
* tests-options.json: Marking test as slow.

Canonical link: https://commits.webkit.org/180622@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@206524 268f45cc-cd09-0410-ab3c-d52691b4dbfc