[Fetch API] Add basic loading of resources

[Fetch API] Add basic loading of resources
https://bugs.webkit.org/show_bug.cgi?id=155637

Reviewed by Darin Adler.

LayoutTests/imported/w3c:

Rebasing test expectations.
Updating scheme-blob.js to ensure generated test names are stable run after run.

* web-platform-tests/fetch/api/basic/accept-header-expected.txt:
* web-platform-tests/fetch/api/basic/integrity-expected.txt:
* web-platform-tests/fetch/api/basic/mode-no-cors-expected.txt:
* web-platform-tests/fetch/api/basic/mode-same-origin-expected.txt:
* web-platform-tests/fetch/api/basic/request-forbidden-headers-expected.txt:
* web-platform-tests/fetch/api/basic/request-headers-expected.txt:
* web-platform-tests/fetch/api/basic/scheme-about-expected.txt:
* web-platform-tests/fetch/api/basic/scheme-blob-expected.txt:
* web-platform-tests/fetch/api/basic/scheme-blob-worker-expected.txt:
* web-platform-tests/fetch/api/basic/scheme-blob.js:
(checkFetchResponse): Deleted.
(checkKoUrl): Deleted.
* web-platform-tests/fetch/api/basic/scheme-data-expected.txt:
* web-platform-tests/fetch/api/basic/scheme-others-expected.txt:
* web-platform-tests/fetch/api/basic/stream-response-expected.txt:

Source/WebCore:

Adding support for basic fetch for Window (no support for Worker yet).
A FetchResponse object is created for every fetch task.
But it will only be exposed to JS at promise fulfillment time, i.e. once initial response headers are retrieved.

Updating Blob resource handle to add Content-Type and Content-Length header and notifying of error in case of erroneous HTTP method.

Fetch is limited to same origin requests currently due to some WPT tests that would timeout otherwise.

Tests: http/tests/fetch/closing-while-fetching.html
       http/tests/fetch/get-response-body-while-loading.html
Also covered by rebased tests.

* Modules/fetch/DOMWindowFetch.cpp: Creating a FetchResponse to start fetching.
(WebCore::DOMWindowFetch::fetch):
* Modules/fetch/DOMWindowFetch.h:
* Modules/fetch/FetchBody.cpp:
(WebCore::FetchBody::consume):
(WebCore::FetchBody::consumeArrayBuffer): Handling of body promises in case of data stored as a buffer.
(WebCore::FetchBody::consumeText): Passing the promise as a reference.
(WebCore::blobFromArrayBuffer): Helper routine.
(WebCore::FetchBody::fulfillTextPromise): Helper routine.
(WebCore::FetchBody::loadedAsArrayBuffer): Updated to handle storing of data as a buffer.
(WebCore::FetchBody::loadedAsText):
(WebCore::FetchBody::bodyForInternalRequest): Helper routine to generate the request body data to be sent as part of the fetch request.
(WebCore::FetchBody::extractFromText):
* Modules/fetch/FetchBody.h:
(WebCore::FetchBody::loadingBody):
(WebCore::FetchBody::FetchBody):
* Modules/fetch/FetchBodyOwner.cpp:
(WebCore::FetchBodyOwner::loadBlob): Updated to cope with the change that FetchLoader::start does not return a boolean anymore
but will directly call failure callbacks.
(WebCore::FetchBodyOwner::loadedBlobAsText): Moving it closer to other blob loading routines.
(WebCore::FetchBodyOwner::finishBlobLoading):
* Modules/fetch/FetchBodyOwner.h:
(WebCore::FetchBodyOwner::body):
(WebCore::FetchBodyOwner::loadedBlobAsArrayBuffer):
* Modules/fetch/FetchHeaders.cpp:
(WebCore::FetchHeaders::fill):
(WebCore::FetchHeaders::filterAndFill): Helper routine to fill headers from a HTTPHeaderMap after being filtered.
* Modules/fetch/FetchHeaders.h:
(WebCore::FetchHeaders::internalHeaders):
* Modules/fetch/FetchLoader.cpp:
(WebCore::FetchLoader::start):
(WebCore::FetchLoader::didFailRedirectCheck):
* Modules/fetch/FetchLoader.h:
* Modules/fetch/FetchRequest.cpp:
(WebCore::FetchRequest::internalRequest): Routine used to create the ResourceRequest transmitted to ThreadableLoader.
       * Modules/fetch/FetchRequest.h:
* Modules/fetch/FetchResponse.cpp:
(WebCore::FetchResponse::fetch): Start fetching by creating a FetchLoader based on passed request.
(WebCore::FetchResponse::BodyLoader::didSucceed): FetchLoader callback.
(WebCore::FetchResponse::BodyLoader::didFail): Ditto.
(WebCore::FetchResponse::BodyLoader::BodyLoader): Ditto.
(WebCore::FetchResponse::BodyLoader::didReceiveResponse): Ditto.
(WebCore::FetchResponse::BodyLoader::didFinishLoadingAsArrayBuffer): Ditto.
(WebCore::FetchResponse::BodyLoader::start): Starting fetch loader.
(WebCore::FetchResponse::BodyLoader::stop): Stopping fetch loader.
(WebCore::FetchResponse::stop): Stop loader if any.
* Modules/fetch/FetchResponse.h:
* platform/network/BlobResourceHandle.cpp:
(WebCore::BlobResourceHandle::doStart: Notifying the loader with an error if verb is not GET.
(WebCore::BlobResourceHandle::notifyResponseOnSuccess): Adding support for Content-Type and Content-Lenth headers.
(WebCore::BlobResourceHandle::createAsync): Removing GET verb check.

LayoutTests:

* TestExpectations: Removed flaky test expectations.
* http/tests/fetch/closing-while-fetching-expected.txt: Added.
* http/tests/fetch/closing-while-fetching.html: Added.
* http/tests/fetch/get-response-body-while-loading-expected.txt: Added.
* http/tests/fetch/get-response-body-while-loading.html: Added.
* http/tests/resources/download-json-with-delay.php: Added.
* platform/gtk/imported/w3c/web-platform-tests/fetch/api/basic/request-headers-expected.txt: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@198665 268f45cc-cd09-0410-ab3c-d52691b4dbfc