Implement 'tabstop' as an HTML attribute

Implement 'tabstop' as an HTML attribute

r190640 introduced 'tabStop' as an property for Element DOM objects.
This CL implements 'tabstop' as an HTML attribute for HTML elements.

The property and attribute is reflected for both direction.
The basic rule is, unless HTML "tabstop" attribute is there
(if tabStop property is set via script, it is reflected in
HTML attribute, so there is), tabStop reflects what
tabindex for the element means.

This is guarded by |tabStopAttribute| runtime features
and only usable when experimental web platform features
flag is enabled.

Design doc:
https://docs.google.com/a/chromium.org/document/d/1k93Ez6yNSyWQDtGjdJJqTBPmljk9l2WS3JTe5OHHB50/edit

BUG=380445
TEST=fast/dom/shadow/tabstop-property.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=192821

[kochi, 2015-03-30 10:38:49]

kochi@chromium.org changed reviewers:
+ hayato@chromium.org

[kochi, 2015-03-30 10:39:46]

PTAL

[hayato, 2015-03-31 05:02:20]

I'm not familiar with how attributes can be implemented.
I'll try to take a look tomorrow (or thu). If you are in hurry, you might want
to add another reviewer who is familiar with attributes.

[kochi, 2015-03-31 05:57:38]

kochi@chromium.org changed reviewers:
+ tkent@chromium.org

[kochi, 2015-03-31 05:57:49]

tkent-san,

Could you review?

[tkent, 2015-03-31 06:16:33]

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
File Source/core/dom/Element.cpp (right):

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
Source/core/dom/Element.cpp:218: if (!hasAttribute(tabstopAttr))
hasAttribute -> fastHasAttribute

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
Source/core/dom/Element.cpp:226: if (!hasAttribute(tabstopAttr))
Ditto.

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
Source/core/dom/Element.cpp:2115: }
What should happen if a string other than "true" "" "false" is specified?


I'm asking "invalid value default" in
https://html.spec.whatwg.org/multipage/infrastructure.html#keywords-and-enume...
.

[kochi, 2015-03-31 08:04:24]

Thanks for the review!

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
File Source/core/dom/Element.cpp (right):

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
Source/core/dom/Element.cpp:218: if (!hasAttribute(tabstopAttr))
On 2015/03/31 06:16:32, tkent wrote:
> hasAttribute -> fastHasAttribute

Done.

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
Source/core/dom/Element.cpp:226: if (!hasAttribute(tabstopAttr))
On 2015/03/31 06:16:32, tkent wrote:
> Ditto.

Done.

https://codereview.chromium.org/1046853002/diff/20001/Source/core/dom/Element...
Source/core/dom/Element.cpp:2115: }
On 2015/03/31 06:16:32, tkent wrote:
> What should happen if a string other than "true" "" "false" is specified?
> 
> 
> I'm asking "invalid value default" in
>
https://html.spec.whatwg.org/multipage/infrastructure.html#keywords-and-enume...
> .

If tabstop is not either of "true", "", "false", it falls back to default state,
as if no tabstop is specified.  In the default state, tabStop value depends on
its tabIndex value (e.g. true on tabindex=0, false on tabindex=-1).

Therefore the case (none of "true" "" "false") the attribute is ignored.

Code to handle the case was missing, so added with layout test change.

[tkent, 2015-03-31 08:11:18]

lgtm

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
File LayoutTests/fast/dom/shadow/tabstop-property.html (right):

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:39:
shouldBe("div.hasAttribute('tabstop')", "false");
nit: shouldBeFalse()

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:46:
shouldBe("div.hasAttribute('tabstop')", "false");
nit: shouldBeFalse()

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:61: shouldBe("div.tabStop",
"false");
nit: shouldBeFalse()

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:79: shouldBe("div.tabStop",
"false");
shouldBeFalse()

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:80:
shouldBe("div.hasAttribute('tabstop')", "false");
shouldBeFalse()

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:93: shouldBe("div.tabStop",
"false");
shouldBeFalse()

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:105: shouldBe("div.tabStop",
"true");
shouldBeTrue()

[kochi, 2015-03-31 08:46:08]

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
File LayoutTests/fast/dom/shadow/tabstop-property.html (right):

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:39:
shouldBe("div.hasAttribute('tabstop')", "false");
On 2015/03/31 08:11:18, tkent wrote:
> nit: shouldBeFalse()

Done.

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:46:
shouldBe("div.hasAttribute('tabstop')", "false");
On 2015/03/31 08:11:18, tkent wrote:
> nit: shouldBeFalse()

Done.

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:61: shouldBe("div.tabStop",
"false");
On 2015/03/31 08:11:18, tkent wrote:
> nit: shouldBeFalse()

Done.

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:79: shouldBe("div.tabStop",
"false");
On 2015/03/31 08:11:18, tkent wrote:
> shouldBeFalse()

Done.

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:80:
shouldBe("div.hasAttribute('tabstop')", "false");
On 2015/03/31 08:11:18, tkent wrote:
> shouldBeFalse()

Done.

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:93: shouldBe("div.tabStop",
"false");
On 2015/03/31 08:11:18, tkent wrote:
> shouldBeFalse()

Done.

https://codereview.chromium.org/1046853002/diff/40001/LayoutTests/fast/dom/sh...
LayoutTests/fast/dom/shadow/tabstop-property.html:105: shouldBe("div.tabStop",
"true");
On 2015/03/31 08:11:18, tkent wrote:
> shouldBeTrue()

Done.

[kochi, 2015-03-31 09:13:33]

The CQ bit was checked by kochi@chromium.org

[kochi, 2015-03-31 09:13:34]

The patchset sent to the CQ was uploaded after l-g-t-m from tkent@chromium.org
Link to the patchset: https://codereview.chromium.org/1046853002/#ps60001
(title: "style nit for layout test.")

[commit-bot: I haz the power, 2015-03-31 09:13:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1046853002/60001

[commit-bot: I haz the power, 2015-03-31 10:18:00]

Committed patchset #4 (id:60001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=192821