Make ApplyStyleCommand::applyRelativeFontStyleChange() to handle AfterAnchor position correctly

Make ApplyStyleCommand::applyRelativeFontStyleChange() to handle AfterAnchor position correctly

This patch makes |ApplyStyleCommand::applyRelativeFontStyleChange()| to stop
node iteration from start position to end node position by using
|Position::nodeAsRangePastLastNode()| instead of |Position::anchorNode()| to
have correct beyond last node in below loop:

Node* beyondLast = end.anchorNode();
for (Node* node = startNode; node != beyondLast;
     node = NodeTraversal::next(node)) {
  ... use |node| ...
}

When |end| is |AfterAnchor| of previous sibling of |startNode|, above loop
doesn't stop.

BUG=619753
TEST=LayoutTests/editing/execCommand/font-size-delta-after-anchor-crash.html

Committed: https://crrev.com/0117448155092540494f302397df47aa8c2bd421
Cr-Commit-Position: refs/heads/master@{#403750}

[yosin_UTC9, 2016-07-05 02:00:01]

Description was changed from

==========
2016-07-04T18:58:53

BUG=
==========

to

==========
Make ApplyStyleCommand::applyRelativeFontStyleChange() to handle AfterAnchor
position correctly

This patch makes |ApplyStyleCommand::applyRelativeFontStyleChange()| to stop
node iteration from start position to end node position by using 
|Position::nodeAsRangePastLastNode()| instead of |Position::anchorNode()| to
have correct beyond last node in below loop:

Node* beyondLast = end.anchorNode();
for (Node* node = startNode; node != beyondLast;
     node = NodeTraversal::next(node)) {
  ... use |node| ...
}

When |end| is |AfterAnchor| of previous sibling of |startNode|, above loop
doesn't stop.

BUG=619753
TEST=LayoutTests/editing/execCommand/font-size-delta-after-anchor-crash.html
==========

[yosin_UTC9, 2016-07-05 03:30:10]

yosin@chromium.org changed reviewers:
+ xiaochengh@chromium.org, yoichio@chromium.org

[yosin_UTC9, 2016-07-05 03:30:10]

PTAL

Bots failures aren't related to this patch.

[Xiaocheng, 2016-07-05 05:27:42]

lgtm

[yoichio, 2016-07-05 05:50:57]

https://codereview.chromium.org/2119083003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/commands/ApplyStyleCommand.cpp
(right):

https://codereview.chromium.org/2119083003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/commands/ApplyStyleCommand.cpp:402: for
(Node* node = startNode; node != beyondEnd; node = NodeTraversal::next(*node)) {
This end condition looks very fragile.
Could you introduce something like |node '<' beyondEnd| or DCHECK it?

[yosin_UTC9, 2016-07-05 07:41:24]

https://codereview.chromium.org/2119083003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/editing/commands/ApplyStyleCommand.cpp
(right):

https://codereview.chromium.org/2119083003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/editing/commands/ApplyStyleCommand.cpp:402: for
(Node* node = startNode; node != beyondEnd; node = NodeTraversal::next(*node)) {
On 2016/07/05 at 05:50:57, yoichio wrote:
> This end condition looks very fragile.
> Could you introduce something like |node '<' beyondEnd| or DCHECK it?

When |beyondEnd| is a wrong value, e.g. |beyondEnd| appears before |startNode|,
it is caught by |DCHECK(node)| in L403.

I don't think we don't need to have  
DCHECK(beyondEnd && (startNode->compareDocumentPosition(beyondEnd) &
Node::DOCUMENT_POSITION_FOLLOWING))

[yosin_UTC9, 2016-07-05 07:41:27]

The CQ bit was checked by yosin@chromium.org

[commit-bot: I haz the power, 2016-07-05 07:41:39]

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, 2016-07-05 07:45:47]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-07-05 07:45:52]

CQ bit was unchecked.

[commit-bot: I haz the power, 2016-07-05 07:48:35]

Description was changed from

==========
Make ApplyStyleCommand::applyRelativeFontStyleChange() to handle AfterAnchor
position correctly

This patch makes |ApplyStyleCommand::applyRelativeFontStyleChange()| to stop
node iteration from start position to end node position by using 
|Position::nodeAsRangePastLastNode()| instead of |Position::anchorNode()| to
have correct beyond last node in below loop:

Node* beyondLast = end.anchorNode();
for (Node* node = startNode; node != beyondLast;
     node = NodeTraversal::next(node)) {
  ... use |node| ...
}

When |end| is |AfterAnchor| of previous sibling of |startNode|, above loop
doesn't stop.

BUG=619753
TEST=LayoutTests/editing/execCommand/font-size-delta-after-anchor-crash.html
==========

to

==========
Make ApplyStyleCommand::applyRelativeFontStyleChange() to handle AfterAnchor
position correctly

This patch makes |ApplyStyleCommand::applyRelativeFontStyleChange()| to stop
node iteration from start position to end node position by using
|Position::nodeAsRangePastLastNode()| instead of |Position::anchorNode()| to
have correct beyond last node in below loop:

Node* beyondLast = end.anchorNode();
for (Node* node = startNode; node != beyondLast;
     node = NodeTraversal::next(node)) {
  ... use |node| ...
}

When |end| is |AfterAnchor| of previous sibling of |startNode|, above loop
doesn't stop.

BUG=619753
TEST=LayoutTests/editing/execCommand/font-size-delta-after-anchor-crash.html

Committed: https://crrev.com/0117448155092540494f302397df47aa8c2bd421
Cr-Commit-Position: refs/heads/master@{#403750}
==========

[commit-bot: I haz the power, 2016-07-05 07:48:36]

Patchset 2 (id:??) landed as
https://crrev.com/0117448155092540494f302397df47aa8c2bd421
Cr-Commit-Position: refs/heads/master@{#403750}