evaluating clipboard event target acording to w3c specification

Make Editor::findEventTargetFrom() to align Clipboard API specification

This patch changes |Editor::findEventTargetFrom()| to return focused element if
selection start is not editable to align Clipboard API specification[1] for
improving interoperability.

[1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event

BUG=690104
TEST=webkit_unittests --gtest_filter=ClipboardEventFlowTest.*

Review-Url: https://codereview.chromium.org/2685723005
Cr-Commit-Position: refs/heads/master@{#451716}
Committed: https://chromium.googlesource.com/chromium/src/+/7afbab0f7619c89aa7a5896024d1628a59cc0ef1

[mwrobel, 2017-02-10 10:27:30]

Description was changed from

==========
issue-690104 evaluating clipboard event target acording to w3c specification

BUG=690104
==========

to

==========
issue-690104 evaluating clipboard event target acording to w3c specification

BUG=690104
==========

[mwrobel, 2017-02-10 10:27:31]

mwrobel@opera.com changed reviewers:
+ ojan@chromium.org, yosin@chromium.org, yutak@chromium.org

[yosin_UTC9, 2017-02-13 04:07:46]

Could you add a test case for this?

We don't need to have "issue-690104" in summary line and please describe what
change you make code.

Thanks!

[mwrobel, 2017-02-13 14:59:07]

I wil try to provide test case once:
https://bugs.chromium.org/p/chromium/issues/detail?id=691532&q=mwrobel%40oper...

is on board

[yosin_UTC9, 2017-02-14 03:46:03]

On 2017/02/13 at 14:59:07, mwrobel wrote:
> I wil try to provide test case once:
>
https://bugs.chromium.org/p/chromium/issues/detail?id=691532&q=mwrobel%40oper...
> 
> is on board

Please add |CORE_EXPORT| to |HTMLButtonElement| class declaration.
webkit_unittests referes |HTMLButtonElement| from blink_core.{dll,so}

[mwrobel, 2017-02-14 17:06:50]

@yosin

test case added

[yosin_UTC9, 2017-02-15 01:30:49]

Could you explain what change you did in this patch?
Also, we don't need to have "issue-690104" in summary line.

Example:

Make Editor::findEventTargetFrom() to align Clipboard API specification

This patch changes |Editor::findEventTargetFrom()| to return focused element if
selection start is not editable to align Clipboard API specification[1] for
improving interoperability.

[1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event

BUG=690104
TEST=webkit_unittests --gtest_filter=ClipboardEventFlowTest.*

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:47: void
setElementTextAndSelectIt(Element& element,
nit: We may want to have a blank line.

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:53: selection
= createVisibleSelection(
You don't need to use |VisibleSelection| here.
You can use FrameSelection::setSelection(const SelectionInDOMTree&) here.

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:69: using
namespace testing;
Please avoid to import all identifiers from namespace[1]:

Excerpt:
You may not use a using-directive to make all names from a namespace available.

// Forbidden -- This pollutes the namespace.
using namespace foo;



[1] https://google.github.io/styleguide/cppguide.html#Namespaces

[mwrobel, 2017-02-15 09:41:23]

Description was changed from

==========
issue-690104 evaluating clipboard event target acording to w3c specification

BUG=690104
==========

to

==========
Make Editor::findEventTargetFrom() to align Clipboard API specification

This patch changes |Editor::findEventTargetFrom()| to return focused element if
selection start is not editable to align Clipboard API specification[1] for
improving interoperability.

[1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event
==========

[mwrobel, 2017-02-15 09:42:26]

Description was changed from

==========
Make Editor::findEventTargetFrom() to align Clipboard API specification

This patch changes |Editor::findEventTargetFrom()| to return focused element if
selection start is not editable to align Clipboard API specification[1] for
improving interoperability.

[1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event
==========

to

==========
Make Editor::findEventTargetFrom() to align Clipboard API specification

This patch changes |Editor::findEventTargetFrom()| to return focused element if
selection start is not editable to align Clipboard API specification[1] for
improving interoperability.

[1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event

BUG=690104
TEST=webkit_unittests --gtest_filter=ClipboardEventFlowTest.*
==========

[mwrobel, 2017-02-15 09:49:53]

On 2017/02/15 01:30:49, yosin_UTC9 wrote:
> Could you explain what change you did in this patch?
> Also, we don't need to have "issue-690104" in summary line.
> 
> Example:
> 
> Make Editor::findEventTargetFrom() to align Clipboard API specification
> 
> This patch changes |Editor::findEventTargetFrom()| to return focused element
if
> selection start is not editable to align Clipboard API specification[1] for
> improving interoperability.
> 
> [1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event
> 
> BUG=690104
> TEST=webkit_unittests --gtest_filter=ClipboardEventFlowTest.*
> 
>
https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp
(right):
> 
>
https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:47: void
> setElementTextAndSelectIt(Element& element,
> nit: We may want to have a blank line.
> 
>
https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:53:
selection
> = createVisibleSelection(
> You don't need to use |VisibleSelection| here.
> You can use FrameSelection::setSelection(const SelectionInDOMTree&) here.
> 
>
https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:69: using
> namespace testing;
> Please avoid to import all identifiers from namespace[1]:
> 
> Excerpt:
> You may not use a using-directive to make all names from a namespace
available.
> 
> // Forbidden -- This pollutes the namespace.
> using namespace foo;
> 
> 
> 
> [1] https://google.github.io/styleguide/cppguide.html#Namespaces

@yosin
thanks for hints ;). All remarks corrected

[yosin_UTC9, 2017-02-15 10:13:58]

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:59:
element.layoutObject()->mutableStyle()->setUserModify(
Accessing layout object is layering violation. Please set "contenteditable"
attribute.

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:96:
EXPECT_EQ(selectionEditable,
We don't need to verify this. Other test verifies FrameSelection::setSelection()

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:101:
EXPECT_CALL(*eventListenerInstalledOnFocusedElement, handleEvent(_, _))
Could you move EXPEC_CALL's L111. Events are fired by document.execCommand().

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:109:
EXPECT_NE(frame().settings(), nullptr);
No need to check this. We'll get SEGV if |!frame().settings()|.

[mwrobel, 2017-02-15 10:51:58]

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:47: void
setElementTextAndSelectIt(Element& element,
On 2017/02/15 01:30:49, yosin_UTC9 wrote:
> nit: We may want to have a blank line.

Done.

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:53: selection
= createVisibleSelection(
On 2017/02/15 01:30:49, yosin_UTC9 wrote:
> You don't need to use |VisibleSelection| here.
> You can use FrameSelection::setSelection(const SelectionInDOMTree&) here.

Done.

https://codereview.chromium.org/2685723005/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:69: using
namespace testing;
On 2017/02/15 01:30:49, yosin_UTC9 wrote:
> Please avoid to import all identifiers from namespace[1]:
> 
> Excerpt:
> You may not use a using-directive to make all names from a namespace
available.
> 
> // Forbidden -- This pollutes the namespace.
> using namespace foo;
> 
> 
> 
> [1] https://google.github.io/styleguide/cppguide.html#Namespaces

Done.

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:59:
element.layoutObject()->mutableStyle()->setUserModify(
On 2017/02/15 10:13:58, yosin_UTC9 wrote:
> Accessing layout object is layering violation. Please set "contenteditable"
> attribute.

Done.

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:96:
EXPECT_EQ(selectionEditable,
On 2017/02/15 10:13:58, yosin_UTC9 wrote:
> We don't need to verify this. Other test verifies
FrameSelection::setSelection()

I wanted to 'show' that test preconditions are met (if they wouldn't then the
whole test doesn't make sense)
p.s.
the same thing goes with expectation on focusableElement

if you still think one (or maybe both?) expectations are not required then
please let me know

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:101:
EXPECT_CALL(*eventListenerInstalledOnFocusedElement, handleEvent(_, _))
On 2017/02/15 10:13:58, yosin_UTC9 wrote:
> Could you move EXPEC_CALL's L111. Events are fired by document.execCommand().

Done.

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:109:
EXPECT_NE(frame().settings(), nullptr);
On 2017/02/15 10:13:58, yosin_UTC9 wrote:
> No need to check this. We'll get SEGV if |!frame().settings()|.

will do (the same goes with setting flag in paste* tests. I will make a change
there to)

[yosin_UTC9, 2017-02-16 10:53:39]

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:96:
EXPECT_EQ(selectionEditable,
On 2017/02/15 at 10:51:58, mwrobel wrote:
> On 2017/02/15 10:13:58, yosin_UTC9 wrote:
> > We don't need to verify this. Other test verifies
FrameSelection::setSelection()
> 
> I wanted to 'show' that test preconditions are met (if they wouldn't then the
whole test doesn't make sense)
> p.s.
> the same thing goes with expectation on focusableElement
> 
> if you still think one (or maybe both?) expectations are not required then
please let me know

I still think precondition checking is not required.
If precondition breaks, it is test bug. In this test, if test doesn't change
editaiblity, one of two tests is failed.
If we really want to check precondition, we need to check shape DOM tree, style
of DOM nodes, dimension of DOM nodes, etc.

https://codereview.chromium.org/2685723005/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:56:
.extend(Position(&element, text.size()))
nit: s/text.size()/1/

It seems |element| has only one child node.


Or
.collapse(Position(element.firstChild(), 0)
.extend(Position(element.firstChild(), text.size()

https://codereview.chromium.org/2685723005/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:95: // double
check test preconditions
I think we don't need to check preconditions.
If these preconditions break, following assertion will be failed too.

[mwrobel, 2017-02-16 11:45:57]

The CQ bit was checked by mwrobel@opera.com

[mwrobel, 2017-02-16 11:45:57]

The CQ bit was unchecked by mwrobel@opera.com

[mwrobel, 2017-02-16 14:15:26]

https://codereview.chromium.org/2685723005/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:56:
.extend(Position(&element, text.size()))
On 2017/02/16 10:53:39, yosin_UTC9 wrote:
> nit: s/text.size()/1/
> 
> It seems |element| has only one child node.
> 
> 
> Or
> .collapse(Position(element.firstChild(), 0)
> .extend(Position(element.firstChild(), text.size()

done (I didn't get your main idea so I used proposal from "Or" part ;))

https://codereview.chromium.org/2685723005/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:95: // double
check test preconditions
On 2017/02/16 10:53:39, yosin_UTC9 wrote:
> I think we don't need to check preconditions.
> If these preconditions break, following assertion will be failed too.

Done.

[yosin_UTC9, 2017-02-17 04:44:23]

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

[yosin_UTC9, 2017-02-17 04:44:24]

lgtm

+tkent@ for HTMLButtonElement.h changes.

[tkent, 2017-02-17 04:55:18]

lgtm

https://codereview.chromium.org/2685723005/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:1: //
Copyright 2016 The Chromium Authors. All rights reserved.
2016 -> 2017

https://codereview.chromium.org/2685723005/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:18: 
This blank line is unnecessary.

[mwrobel, 2017-02-17 07:59:23]

https://codereview.chromium.org/2685723005/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp (right):

https://codereview.chromium.org/2685723005/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:1: //
Copyright 2016 The Chromium Authors. All rights reserved.
On 2017/02/17 04:55:18, tkent wrote:
> 2016 -> 2017

Done.

https://codereview.chromium.org/2685723005/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/ClipboardEventFlowTest.cpp:18: 
On 2017/02/17 04:55:18, tkent wrote:
> This blank line is unnecessary.

Done.

[mwrobel, 2017-02-17 08:06:30]

The CQ bit was checked by mwrobel@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2017-02-17 08:06:55]

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, 2017-02-17 08:06:59]

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

[commit-bot: I haz the power, 2017-02-17 08:07:01]

Dry run: The author mwrobel@opera.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[mwrobel, 2017-02-17 09:20:23]

this is my first patch. Could you please run tests (and generally integrate it)?

[tkent, 2017-02-17 09:26:55]

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

[commit-bot: I haz the power, 2017-02-17 09:27:04]

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, 2017-02-17 09:27:05]

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

[commit-bot: I haz the power, 2017-02-17 09:27:06]

Dry run: The author mwrobel@opera.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[sof, 2017-02-17 09:45:50]

The CQ bit was checked by sigbjornf@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2017-02-17 09:46:07]

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, 2017-02-17 09:46:08]

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

[commit-bot: I haz the power, 2017-02-17 09:46:09]

Dry run: The author mwrobel@opera.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[sof, 2017-02-17 09:48:00]

The CQ bit was checked by sigbjornf@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2017-02-17 09:48:22]

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, 2017-02-17 09:48:23]

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

[commit-bot: I haz the power, 2017-02-17 09:48:24]

Dry run: The author mwrobel@opera.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[sof, 2017-02-17 09:52:59]

CQ balks at https://codereview.chromium.org/2685723005/#msg30 .
mwrobel@opera.com should be covered by the *@opera.com entry in //AUTHORS
afaict. ?

[sof, 2017-02-17 12:43:01]

The CQ bit was checked by sigbjornf@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2017-02-17 12:43:22]

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

[sof, 2017-02-17 12:45:14]

On 2017/02/17 09:52:59, sof wrote:
> CQ balks at https://codereview.chromium.org/2685723005/#msg30 .
> mailto:mwrobel@opera.com should be covered by the mailto:*@opera.com entry in
//AUTHORS
> afaict. ?

Handled; had to add mwrobel@ to a separate Opera list.

[commit-bot: I haz the power, 2017-02-17 13:50:23]

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

[commit-bot: I haz the power, 2017-02-17 13:50:24]

Dry run: Try jobs failed on following builders:
  win_chromium_x64_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[mwrobel, 2017-02-20 12:16:11]

@yosin

please double check additional change (I had to change single webkit test) since
when selection is not editable event target is expected to be on active element
and when there is no active element (like in changed test exapmle) in body.

[mwrobel, 2017-02-20 12:16:35]

The CQ bit was checked by mwrobel@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2017-02-20 12:16:52]

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, 2017-02-20 13:21:52]

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

[commit-bot: I haz the power, 2017-02-20 13:21:53]

Dry run: Try jobs failed on following builders:
  ios-simulator on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/bui...)

[mwrobel, 2017-02-20 13:54:26]

The CQ bit was checked by mwrobel@opera.com

[mwrobel, 2017-02-20 13:54:27]

The patchset sent to the CQ was uploaded after l-g-t-m from tkent@chromium.org,
yosin@chromium.org
Link to the patchset: https://codereview.chromium.org/2685723005/#ps120001
(title: "Make Editor::findEventTargetFrom() to align Clipboard API
specification")

[mwrobel, 2017-02-20 13:54:27]

The CQ bit was unchecked by mwrobel@opera.com

[mwrobel, 2017-02-21 08:31:10]

The CQ bit was checked by mwrobel@opera.com

[mwrobel, 2017-02-21 08:31:11]

The patchset sent to the CQ was uploaded after l-g-t-m from tkent@chromium.org,
yosin@chromium.org
Link to the patchset: https://codereview.chromium.org/2685723005/#ps120001
(title: "Make Editor::findEventTargetFrom() to align Clipboard API
specification")

[mwrobel, 2017-02-21 08:31:16]

The CQ bit was unchecked by mwrobel@opera.com

[mwrobel, 2017-02-21 08:31:17]

The CQ bit was checked by mwrobel@opera.com

[commit-bot: I haz the power, 2017-02-21 08:31:41]

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, 2017-02-21 09:34:42]

CQ is committing da patch.

Bot data: {"patchset_id": 120001, "attempt_start_ts": 1487665877175940,
"parent_rev": "2f16bd68bd7e191db66f96d2c761017902074d91", "commit_rev":
"7afbab0f7619c89aa7a5896024d1628a59cc0ef1"}

[commit-bot: I haz the power, 2017-02-21 09:35:20]

Description was changed from

==========
Make Editor::findEventTargetFrom() to align Clipboard API specification

This patch changes |Editor::findEventTargetFrom()| to return focused element if
selection start is not editable to align Clipboard API specification[1] for
improving interoperability.

[1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event

BUG=690104
TEST=webkit_unittests --gtest_filter=ClipboardEventFlowTest.*
==========

to

==========
Make Editor::findEventTargetFrom() to align Clipboard API specification

This patch changes |Editor::findEventTargetFrom()| to return focused element if
selection start is not editable to align Clipboard API specification[1] for
improving interoperability.

[1] https://w3c.github.io/clipboard-apis/#to-fire-a-clipboard-event

BUG=690104
TEST=webkit_unittests --gtest_filter=ClipboardEventFlowTest.*

Review-Url: https://codereview.chromium.org/2685723005
Cr-Commit-Position: refs/heads/master@{#451716}
Committed:
https://chromium.googlesource.com/chromium/src/+/7afbab0f7619c89aa7a5896024d1...
==========

[commit-bot: I haz the power, 2017-02-21 09:35:25]

Committed patchset #7 (id:120001) as
https://chromium.googlesource.com/chromium/src/+/7afbab0f7619c89aa7a5896024d1...

[yosin_UTC9, 2017-02-22 07:38:46]

On 2017/02/21 at 09:35:25, commit-bot wrote:
> Committed patchset #7 (id:120001) as
https://chromium.googlesource.com/chromium/src/+/7afbab0f7619c89aa7a5896024d1...

lgtm

Thanks for fixing!

[luoe, 2017-03-10 18:08:21]

A revert of this CL (patchset #7 id:120001) has been created in
https://codereview.chromium.org/2745813002/ by luoe@chromium.org.

The reason for reverting is: Changing this functionality improved spec
conformance, but introduced regressions where text that used to be copied is no
longer copied:
crbug.com/695568
crbug.com/700163

A proposal to change the spec was made here:
https://github.com/w3c/clipboard-apis/issues/40.