Make removeChild faster with active ranges

Make removeChild/remove faster with active Range objects

This patch makes |Node#removeChild()| and |Node#remove()| faster when
there are active Range objects in document by using DOM tree version as
offset validity instead of invalid offset value on node removal, which is
done by |Range::nodeChildrenChanged()| via
|Document::updateRangesAfterChildrenChanged()|.

This patch is similar to http://crrev.com/2034023003, which makes appendChild
and insertBefore faster.

On my Linux box, "remove-child-with-ranges.html" (with 1000 |Range| objects)
results are:

w/patch:
avg 0.96 runs/s, median 1.00 runs/s, min 0.80 runs/s, max 1.03 runs/s

w/o patch:
avg 0.69 runs/s, median 0.71 runs/s, min 0.56 runs/s, max 0.76 runs/s

BUG=n/a
TEST=PerformanceTests/Mutation/remove-child-with-ranges.html

Committed: https://crrev.com/6d90de9c8429ea28e578ff42ed6e2d35d963722b
Cr-Commit-Position: refs/heads/master@{#397993}

[yosin_UTC9, 2016-06-06 07:32:58]

Description was changed from

==========
2016-06-06T14:55:55

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

to

==========
Make removeChild/remove faster with active Range objects

This patch makes |Node#removeChild()| and |Node#remove()| faster when
there are active Range objects in document by using DOM tree version as
offset validity instead of invalid offset value on node removal, which is
done by |Range::nodeChildrenChanged()| via
|Document::updateRangesAfterChildrenChanged()|.

This patch is similar to http://crrev.com/2034023003, which makes appendChild
and insertBefore faster.

On my Linux box, "remove-child-with-ranges.html" (with 1000 |Range| objects)
results are:

w/patch:
avg 0.96 runs/s, median 1.00 runs/s, min 0.80 runs/s, max 1.03 runs/s

w/o patch:
avg 0.69 runs/s, median 0.71 runs/s, min 0.56 runs/s, max 0.76 runs/s

BUG=n/a
TEST=PerformanceTests/Mutation/remove-child-with-ranges.html
==========

[yosin_UTC9, 2016-06-06 07:33:56]

yosin@chromium.org changed reviewers:
+ keishi@chromium.org, kouhei@chromium.org

[yosin_UTC9, 2016-06-06 07:33:56]

PTAL

Applying appendChild optimization to removeChild. It makes source code simpler
too.

[kouhei (in TOK), 2016-06-06 07:39:11]

lgtm % test pass

[yosin_UTC9, 2016-06-06 07:57:00]

The CQ bit was checked by yosin@chromium.org

[commit-bot: I haz the power, 2016-06-06 07:57:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2039113003/20001

[commit-bot: I haz the power, 2016-06-06 09:08:46]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-06 09:10:47]

Description was changed from

==========
Make removeChild/remove faster with active Range objects

This patch makes |Node#removeChild()| and |Node#remove()| faster when
there are active Range objects in document by using DOM tree version as
offset validity instead of invalid offset value on node removal, which is
done by |Range::nodeChildrenChanged()| via
|Document::updateRangesAfterChildrenChanged()|.

This patch is similar to http://crrev.com/2034023003, which makes appendChild
and insertBefore faster.

On my Linux box, "remove-child-with-ranges.html" (with 1000 |Range| objects)
results are:

w/patch:
avg 0.96 runs/s, median 1.00 runs/s, min 0.80 runs/s, max 1.03 runs/s

w/o patch:
avg 0.69 runs/s, median 0.71 runs/s, min 0.56 runs/s, max 0.76 runs/s

BUG=n/a
TEST=PerformanceTests/Mutation/remove-child-with-ranges.html
==========

to

==========
Make removeChild/remove faster with active Range objects

This patch makes |Node#removeChild()| and |Node#remove()| faster when
there are active Range objects in document by using DOM tree version as
offset validity instead of invalid offset value on node removal, which is
done by |Range::nodeChildrenChanged()| via
|Document::updateRangesAfterChildrenChanged()|.

This patch is similar to http://crrev.com/2034023003, which makes appendChild
and insertBefore faster.

On my Linux box, "remove-child-with-ranges.html" (with 1000 |Range| objects)
results are:

w/patch:
avg 0.96 runs/s, median 1.00 runs/s, min 0.80 runs/s, max 1.03 runs/s

w/o patch:
avg 0.69 runs/s, median 0.71 runs/s, min 0.56 runs/s, max 0.76 runs/s

BUG=n/a
TEST=PerformanceTests/Mutation/remove-child-with-ranges.html

Committed: https://crrev.com/6d90de9c8429ea28e578ff42ed6e2d35d963722b
Cr-Commit-Position: refs/heads/master@{#397993}
==========

[commit-bot: I haz the power, 2016-06-06 09:10:48]

Patchset 2 (id:??) landed as
https://crrev.com/6d90de9c8429ea28e578ff42ed6e2d35d963722b
Cr-Commit-Position: refs/heads/master@{#397993}