Blur immediately if an attribute change made an element unfocasable.

Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999
Committed: https://crrev.com/40ccb2581137efc2fc7d2a1041073fa00caed75a
Cr-Commit-Position: refs/heads/master@{#440063}

[tkent, 2016-12-20 01:25:20]

The CQ bit was checked by tkent@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-20 01:25:50]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-20 03:26:15]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-20 03:26:16]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[tkent, 2016-12-20 04:11:43]

The CQ bit was checked by tkent@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-20 04:12:04]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[tkent, 2016-12-20 04:14:48]

The CQ bit was checked by tkent@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-20 04:15:08]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[tkent, 2016-12-20 04:35:02]

Patchset #1 (id:1) has been deleted

[tkent, 2016-12-20 04:35:10]

Patchset #1 (id:20001) has been deleted

[tkent, 2016-12-20 06:11:37]

Description was changed from

==========
html: Blur immediately if an attribute change made an element unfocasable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetlElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999
==========

to

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999
==========

[commit-bot: I haz the power, 2016-12-20 06:58:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-20 06:58:17]

Dry run: This issue passed the CQ dry run.

[tkent, 2016-12-20 07:02:04]

Description was changed from

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999
==========

to

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

* 

BUG=660999
==========

[tkent, 2016-12-20 07:03:17]

Description was changed from

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

* 

BUG=660999
==========

to

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

* focus-fixup-rule-one-no-dialogs.html
  This CL imports the latest revision of focus-fixup-rule-one-no-dialogs.html
  from web-platform-tests.  It will be updated by the next WPT auto-roll.

BUG=660999
==========

[tkent, 2016-12-20 07:03:29]

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

[tkent, 2016-12-20 07:03:30]

kochi@, would you review this please?

[tkent, 2016-12-20 07:20:05]

Description was changed from

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

* focus-fixup-rule-one-no-dialogs.html
  This CL imports the latest revision of focus-fixup-rule-one-no-dialogs.html
  from web-platform-tests.  It will be updated by the next WPT auto-roll.

BUG=660999
==========

to

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

* focus-fixup-rule-one-no-dialogs.html
  This CL imports the latest revision of focus-fixup-rule-one-no-dialogs.html
  from web-platform-tests.  It will be updated by the next WPT auto-roll.

BUG=660999
NOEXPORT=true
==========

[tkent, 2016-12-21 04:02:45]

The CQ bit was checked by tkent@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-21 04:03:02]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[tkent, 2016-12-21 04:03:35]

Description was changed from

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

* focus-fixup-rule-one-no-dialogs.html
  This CL imports the latest revision of focus-fixup-rule-one-no-dialogs.html
  from web-platform-tests.  It will be updated by the next WPT auto-roll.

BUG=660999
NOEXPORT=true
==========

to

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999
==========

[commit-bot: I haz the power, 2016-12-21 05:39:52]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-21 05:39:53]

Dry run: This issue passed the CQ dry run.

[kochi, 2016-12-21 05:58:09]

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/dom/Element.cpp (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/dom/Element.cpp:1317: // to call it, and it needs
up-to-date style.
nit: s/avoid to call/avoid calling/

Let me understand the comment correctly.
"depends on element classes" = supportsFocus() is virtual for
element C++ classes?  I'm not sure why "It's hard to avoid" from
the comment.

Does the below sound correct?
// The attribute change may cause supportsFocus() to return false
// for the element which had focus, because some elements use
// attributes and up-to-date style to determine focusability.

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/dom/Element.h (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/dom/Element.h:373: // implementation needs to
check an attribute update, we should override this
nit: avoid "we" and just "override this function" sounds fine.

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/html/HTMLFieldSetElement.cpp (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/html/HTMLFieldSetElement.cpp:67: Element*
HTMLFieldSetElement::invalidateDisabledStateUnder(Element& base) {
The name of the function and return value seem irrelevant.

[tkent, 2016-12-21 06:51:15]

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/dom/Element.cpp (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/dom/Element.cpp:1317: // to call it, and it needs
up-to-date style.
On 2016/12/21 at 05:58:09, kochi wrote:
> nit: s/avoid to call/avoid calling/
> 
> Let me understand the comment correctly.
> "depends on element classes" = supportsFocus() is virtual for
> element C++ classes?  I'm not sure why "It's hard to avoid" from
> the comment.

We don't call supportsFocus() and updateStyleAndLayoutTreeForNode() for |href|
and |disabled| attribute change because their behavior are fixed.
tabindex change won't affect style, so I'm unwilling to call
updateStyleAndLayoutTreeForNode().

> Does the below sound correct?
> // The attribute change may cause supportsFocus() to return false
> // for the element which had focus, because some elements use
> // attributes and up-to-date style to determine focusability.

This is also correct though it doesn't include the unwillingness of
updateStyleAndLayoutTreeForNode().
Your comment and a TODO() would be better?

// The attribute change may cause supportsFocus() to return false
// for the element which had focus, because some elements use
// attributes and up-to-date style to determine focusability.
// TODO(tkent): tabindex doesn't affect style. We should avoid to
// update style if possible.

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/dom/Element.h (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/dom/Element.h:373: // implementation needs to
check an attribute update, we should override this
On 2016/12/21 at 05:58:09, kochi wrote:
> nit: avoid "we" and just "override this function" sounds fine.

Will do.

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/html/HTMLFieldSetElement.cpp (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/html/HTMLFieldSetElement.cpp:67: Element*
HTMLFieldSetElement::invalidateDisabledStateUnder(Element& base) {
On 2016/12/21 at 05:58:09, kochi wrote:
> The name of the function and return value seem irrelevant.

invalidateDescendantDisabledStateAndFindFocusedOne ?

[tkent, 2016-12-21 07:30:10]

The CQ bit was checked by tkent@chromium.org to run a CQ dry run

[tkent, 2016-12-21 07:30:25]

Uploaded a new patch set.

[commit-bot: I haz the power, 2016-12-21 07:30:25]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[kochi, 2016-12-21 08:05:19]

lgtm

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/dom/Element.cpp (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/dom/Element.cpp:1317: // to call it, and it needs
up-to-date style.
On 2016/12/21 06:51:15, slow_or_unavailable wrote:
> On 2016/12/21 at 05:58:09, kochi wrote:
> > nit: s/avoid to call/avoid calling/
> > 
> > Let me understand the comment correctly.
> > "depends on element classes" = supportsFocus() is virtual for
> > element C++ classes?  I'm not sure why "It's hard to avoid" from
> > the comment.
> 
> We don't call supportsFocus() and updateStyleAndLayoutTreeForNode() for |href|
> and |disabled| attribute change because their behavior are fixed.
> tabindex change won't affect style, so I'm unwilling to call
> updateStyleAndLayoutTreeForNode().
> 
> > Does the below sound correct?
> > // The attribute change may cause supportsFocus() to return false
> > // for the element which had focus, because some elements use
> > // attributes and up-to-date style to determine focusability.
> 
> This is also correct though it doesn't include the unwillingness of
> updateStyleAndLayoutTreeForNode().
> Your comment and a TODO() would be better?
> 
> // The attribute change may cause supportsFocus() to return false
> // for the element which had focus, because some elements use
> // attributes and up-to-date style to determine focusability.
> // TODO(tkent): tabindex doesn't affect style. We should avoid to
> // update style if possible.

Looks good.

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/html/HTMLFieldSetElement.cpp (right):

https://codereview.chromium.org/2586143004/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/html/HTMLFieldSetElement.cpp:67: Element*
HTMLFieldSetElement::invalidateDisabledStateUnder(Element& base) {
On 2016/12/21 06:51:15, slow_or_unavailable wrote:
> On 2016/12/21 at 05:58:09, kochi wrote:
> > The name of the function and return value seem irrelevant.
> 
> invalidateDescendantDisabledStateAndFindFocusedOne ?

Yeah, long but readable.
As the function only called from 2 functions below, and they
can fit in one screen - so we should not worry too much about
the naming :)

[commit-bot: I haz the power, 2016-12-21 09:35:12]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-21 09:35:13]

Dry run: This issue passed the CQ dry run.

[tkent, 2016-12-21 09:40:55]

The CQ bit was checked by tkent@chromium.org

[commit-bot: I haz the power, 2016-12-21 09:41:07]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-21 09:45:50]

CQ is committing da patch.

Bot data: {"patchset_id": 60002, "attempt_start_ts": 1482313255583150,
"parent_rev": "9af62c6788527951008494f02ae629a6c499bb80", "commit_rev":
"e01054e20d1f35c2a5b802fd63c690cad7266dbe"}

[commit-bot: I haz the power, 2016-12-21 09:46:15]

Description was changed from

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999
==========

to

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999

Review-Url: https://codereview.chromium.org/2586143004
==========

[commit-bot: I haz the power, 2016-12-21 09:46:16]

Committed patchset #3 (id:60002)

[commit-bot: I haz the power, 2016-12-21 09:48:49]

Description was changed from

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999

Review-Url: https://codereview.chromium.org/2586143004
==========

to

==========
Blur immediately if an attribute change made an element unfocusable.

tabindex, hidden, contenteditable, disabled, href attributes affect element
focusability, however we didn't remove focus from the element immediately after
an attribute change made the element unfocusable because dispatching events in
parseAttribute() looks dangerous. Actually, dispatching events for update of
some specific attributes in parseAttribute() can cause bugs.

With this CL, we remove focus in Element::attributeChanged().

* Element::AttributeModificationReason
  Add kByParser, and update existing item names.
  We don't check focusability for kByParser and kByCloning because the element
  can't be focused in these cases.

* Element::attributeChanged()
  Stop using a default argument.
  Move focus check for tabindex change from parseAttribute().

* HTMLAnchorElement
  Move focus check for href change from parseAttribute() to attributeChanged().

* HTMLElement
  Move focus check for hidden and contenteditable change from parseAttribute()
  to attributeChanged().

* HTMLFormControlElement
  Move focus check for disabled change from parseAttribute() to
  attributeChanged().

* HTMLFieldSetElement
  Check focusability of descendant form controls when the fieldset element is
  disabled, or a legend element is inserted.

BUG=660999

Committed: https://crrev.com/40ccb2581137efc2fc7d2a1041073fa00caed75a
Cr-Commit-Position: refs/heads/master@{#440063}
==========

[commit-bot: I haz the power, 2016-12-21 09:48:51]

Patchset 3 (id:??) landed as
https://crrev.com/40ccb2581137efc2fc7d2a1041073fa00caed75a
Cr-Commit-Position: refs/heads/master@{#440063}