Merge "CSS Selector: Fix a regression of :first-child and :last-child invalidation" to M58.

Merge "CSS Selector: Fix a regression of :first-child and :last-child invalidation" to M58.

https://codereview.chromium.org/2306323002 caused a regression of :first-child and
:last-child invalidation because the timing of ContainerNode::childrenChanged was
slightly changed for multiple nodes insertion.
 Before: childrenChanged was called on every node insertion
 After: childrenChanged was called after inserting all nodes

This CL changes the definition of ChildrenChanged::siblingBeforeChange and
siblingAfterChange so that they always point existing nodes before insertion
operations. It fixes the behavior of ContainerNode::checkForSiblingStyleChanges,
which is called from Element::childrenChanged and ShadowRoot::childrenChanged.
siblingBeforeChange and siblingAfterChange are used only by
checkForSiblingStyleChanges.  So this definition change is safe.

BUG=702104
Review-Url: https://codereview.chromium.org/2772463004
Cr-Commit-Position: refs/heads/master@{#459023}
(cherry picked from commit e89e9ca08e4abca7bf13d7424434b301caf5b4a5)

Review-Url: https://codereview.chromium.org/2774753003 .
Cr-Commit-Position: refs/branch-heads/3029@{#405}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/404689093a8d2aeb6345635948f614e35d0fdf3a

[tkent, 2017-03-24 08:20:45]

Description was changed from

==========
Merge "CSS Selector: Fix a regression of :first-child and :last-child
invalidation" to M58.

https://codereview.chromium.org/2306323002 caused a regression of :first-child
and
:last-child invalidation because the timing of ContainerNode::childrenChanged
was
slightly changed for multiple nodes insertion.
 Before: childrenChanged was called on every node insertion
 After: childrenChanged was called after inserting all nodes

This CL changes the definition of ChildrenChanged::siblingBeforeChange and
siblingAfterChange so that they always point existing nodes before insertion
operations. It fixes the behavior of ContainerNode::checkForSiblingStyleChanges,
which is called from Element::childrenChanged and ShadowRoot::childrenChanged.
siblingBeforeChange and siblingAfterChange are used only by
checkForSiblingStyleChanges.  So this definition change is safe.

BUG=702104

Review-Url: https://codereview.chromium.org/2772463004
Cr-Commit-Position: refs/heads/master@{#459023}
(cherry picked from commit e89e9ca08e4abca7bf13d7424434b301caf5b4a5)
==========

to

==========
Merge "CSS Selector: Fix a regression of :first-child and :last-child
invalidation" to M58.

https://codereview.chromium.org/2306323002 caused a regression of :first-child
and
:last-child invalidation because the timing of ContainerNode::childrenChanged
was
slightly changed for multiple nodes insertion.
 Before: childrenChanged was called on every node insertion
 After: childrenChanged was called after inserting all nodes

This CL changes the definition of ChildrenChanged::siblingBeforeChange and
siblingAfterChange so that they always point existing nodes before insertion
operations. It fixes the behavior of ContainerNode::checkForSiblingStyleChanges,
which is called from Element::childrenChanged and ShadowRoot::childrenChanged.
siblingBeforeChange and siblingAfterChange are used only by
checkForSiblingStyleChanges.  So this definition change is safe.

BUG=702104

Review-Url: https://codereview.chromium.org/2772463004
Cr-Commit-Position: refs/heads/master@{#459023}
(cherry picked from commit e89e9ca08e4abca7bf13d7424434b301caf5b4a5)

Review-Url: https://codereview.chromium.org/2774753003 .
Cr-Commit-Position: refs/branch-heads/3029@{#405}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/404689093a8d2aeb6345635948f6...
==========

[tkent, 2017-03-24 08:20:47]

Committed patchset #1 (id:1) manually as
404689093a8d2aeb6345635948f614e35d0fdf3a.