[Fetch API] Add support for fetch mode, in particular cors

[Fetch API] Add support for fetch mode, in particular cors
https://bugs.webkit.org/show_bug.cgi?id=156753

Patch by Youenn Fablet <youenn@apple.com> on 2016-07-26
Reviewed by Darin Adler.

LayoutTests/imported/w3c:

Rebasing tests.

* web-platform-tests/fetch/api/basic/integrity-expected.txt:
* web-platform-tests/fetch/api/basic/integrity-worker-expected.txt:
* web-platform-tests/fetch/api/basic/mode-no-cors-expected.txt:
* web-platform-tests/fetch/api/basic/mode-no-cors-worker-expected.txt:
* web-platform-tests/fetch/api/cors/cors-basic-expected.txt:
* web-platform-tests/fetch/api/cors/cors-basic-worker-expected.txt:
* web-platform-tests/fetch/api/cors/cors-cookies-expected.txt:
* web-platform-tests/fetch/api/cors/cors-cookies-worker-expected.txt:
* web-platform-tests/fetch/api/cors/cors-filtering-expected.txt:
* web-platform-tests/fetch/api/cors/cors-filtering-worker-expected.txt:
* web-platform-tests/fetch/api/cors/cors-multiple-origins-expected.txt:
* web-platform-tests/fetch/api/cors/cors-multiple-origins-worker-expected.txt:
* web-platform-tests/fetch/api/cors/cors-preflight-expected.txt:
* web-platform-tests/fetch/api/cors/cors-preflight-referrer-worker-expected.txt:
* web-platform-tests/fetch/api/cors/cors-preflight-worker-expected.txt:
* web-platform-tests/fetch/api/cors/cors-redirect-credentials-expected.txt:
* web-platform-tests/fetch/api/cors/cors-redirect-credentials-worker-expected.txt:
* web-platform-tests/fetch/api/credentials/authentication-basic-worker-expected.txt:
* web-platform-tests/fetch/api/request/request-cache-expected.txt:

Source/WebCore:

Covered by rebased tests.

* Modules/fetch/FetchLoader.cpp:
(WebCore::FetchLoader::start): Passing fetch mode to ThreadableLoader.
Disabling as a temp fix credentials in case of CORS mode as credential options is not yet supported and would make several tests fail.

LayoutTests:

Rebasing specific expectations as Maci/iOS WK2 does not like https tests.

* platform/ios-simulator-wk2/imported/w3c/web-platform-tests/fetch/api/basic/mode-no-cors-expected.txt: Added.
* platform/ios-simulator-wk2/imported/w3c/web-platform-tests/fetch/api/basic/mode-no-cors-worker-expected.txt: Added.
* platform/ios-simulator-wk2/imported/w3c/web-platform-tests/fetch/api/cors/cors-basic-expected.txt: Added.
* platform/ios-simulator-wk2/imported/w3c/web-platform-tests/fetch/api/cors/cors-basic-worker-expected.txt: Added.
* platform/mac-wk2/imported/w3c/web-platform-tests/fetch/api/basic/mode-no-cors-expected.txt: Added.
* platform/mac-wk2/imported/w3c/web-platform-tests/fetch/api/basic/mode-no-cors-worker-expected.txt: Added.
* platform/mac-wk2/imported/w3c/web-platform-tests/fetch/api/cors/cors-basic-expected.txt: Added.
* platform/mac-wk2/imported/w3c/web-platform-tests/fetch/api/cors/cors-basic-worker-expected.txt: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@203732 268f45cc-cd09-0410-ab3c-d52691b4dbfc