Settings a reflected DOMString attribute to null should set it to the "null" string rather than the empty string

[Chris Dumez]

Settings a reflected DOMString attribute to null should set it to the "null" string rather than the empty string:
- https://html.spec.whatwg.org/#reflecting-content-attributes-in-idl-attributes
- http://heycam.github.io/webidl/#es-DOMString
- http://people.mozilla.org/~jorendorff/es6-draft.html#sec-tostring

Firefox and Chrome match the specification here.

This is causing a lot of W3C HTML reflection tests to fail on WebKit, e.g.:
http://w3c-test.org/html/dom/reflection-text.html

[Radar WebKit Bug Importer]

<rdar://problem/24353072>

[Chris Dumez]

Created attachment 269939 [details]
WIP Patch

[Chris Dumez]

Created attachment 269974 [details]
Patch

[Chris Dumez]

Created attachment 270006 [details]
Patch

[Ryosuke Niwa]

Comment on attachment 270006 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=270006&action=review

> LayoutTests/fast/shadow-dom/HTMLSlotElement-interface.html:105
>      slotElement.name = null;

This should be slotElement.removeAttribute('name') instead.

> LayoutTests/fast/shadow-dom/NonDocumentTypeChildNode-interface-assignedSlot.html:80
>      slot.name = null;

Ditto.

[Chris Dumez]

Created attachment 270038 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 270038 [details]
Patch

Rejecting attachment 270038 [details] from commit-queue.

Failed to run "['/Volumes/Data/EWS/WebKit/Tools/Scripts/webkit-patch', '--status-host=webkit-queues.webkit.org', '--bot-id=webkit-cq-02', 'apply-attachment', '--no-update', '--non-interactive', 270038, '--port=mac']" exit_code: 2 cwd: /Volumes/Data/EWS/WebKit

Last 500 characters of output:
atching file LayoutTests/fast/shadow-dom/NonDocumentTypeChildNode-interface-assignedSlot.html
Hunk #1 succeeded at 82 with fuzz 2 (offset 5 lines).
patching file LayoutTests/fast/shadow-dom/shadow-layout-after-slot-changes.html
patching file LayoutTests/svg/dom/svg-element-attribute-js-null-expected.txt
patching file LayoutTests/svg/dom/svg-element-attribute-js-null.xhtml

Failed to run "[u'/Volumes/Data/EWS/WebKit/Tools/Scripts/svn-apply', '--force']" exit_code: 1 cwd: /Volumes/Data/EWS/WebKit

Full output: http://webkit-queues.webkit.org/results/747095

[Chris Dumez]

Created attachment 270039 [details]
Patch

[Chris Dumez]

Created attachment 270045 [details]
Patch

[Chris Dumez]

Created attachment 270046 [details]
Patch

[Chris Dumez]

Comment on attachment 270046 [details]
Patch

Clearing flags on attachment: 270046

Committed r195700: <http://trac.webkit.org/changeset/195700>

[Chris Dumez]

All reviewed patches have been landed.  Closing bug.