Track lastTextNode during rebuildLayoutTree.

Track lastTextNode during rebuildLayoutTree.

We keep track of last seen text node for more efficient whitespace
re-attachment. When style recalc and layout tree building was split,
the text node is still tracked during recalc, stored in a hash map, and
retreived when needed during layout tree building.

However, the text nodes are also traversed during layout tree building
so that we can track the nodes during that phase instead.
StyleReattachData is removed and this CL reverts back to using the
m_nonAttachedStyle map for ComputedStyle.

The comment about reversed traversal of children for avoiding n^2
performance is moved to rebuildChildrenLayoutTrees() since that's where
the issue is. We should be able to do the child recalc first-to-last
now if we want to.

R=nainar@chromium.org,esprehn@chromium.org
BUG=595137
Review-Url: https://codereview.chromium.org/2740823005
Cr-Commit-Position: refs/heads/master@{#456047}
Committed: https://chromium.googlesource.com/chromium/src/+/af8b67666d6c89aec9abebe7df21a2732d91ea2a

[rune, 2017-03-09 23:39:59]

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

[commit-bot: I haz the power, 2017-03-09 23:40:43]

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

[rune, 2017-03-10 00:25:08]

ptal

Hope this doesn't interfere too much with your work Naina.

[nainar, 2017-03-10 00:30:21]

This change makes sense and lgtm - thank you for making it! Making the HashMap's
size smaller is a great change! So thank you!

[commit-bot: I haz the power, 2017-03-10 01:04:49]

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

[commit-bot: I haz the power, 2017-03-10 01:04:50]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[esprehn, 2017-03-10 02:42:48]

lgtm

[rune, 2017-03-10 10:41:45]

The CQ bit was checked by rune@opera.com

[rune, 2017-03-10 10:41:46]

The patchset sent to the CQ was uploaded after l-g-t-m from nainar@chromium.org,
esprehn@chromium.org
Link to the patchset: https://codereview.chromium.org/2740823005/#ps20001
(title: "Missing reset of lastTextNode for elements.")

[commit-bot: I haz the power, 2017-03-10 10:41:54]

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, 2017-03-10 12:36:51]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1489142505733740,
"parent_rev": "9b207c01a4d7df3381eb1fefc6d62be7847e1365", "commit_rev":
"af8b67666d6c89aec9abebe7df21a2732d91ea2a"}

[commit-bot: I haz the power, 2017-03-10 12:37:26]

Description was changed from

==========
Track lastTextNode during rebuildLayoutTree.

We keep track of last seen text node for more efficient whitespace
re-attachment. When style recalc and layout tree building was split,
the text node is still tracked during recalc, stored in a hash map, and
retreived when needed during layout tree building.

However, the text nodes are also traversed during layout tree building
so that we can track the nodes during that phase instead.
StyleReattachData is removed and this CL reverts back to using the
m_nonAttachedStyle map for ComputedStyle.

The comment about reversed traversal of children for avoiding n^2
performance is moved to rebuildChildrenLayoutTrees() since that's where
the issue is. We should be able to do the child recalc first-to-last
now if we want to.

R=nainar@chromium.org,esprehn@chromium.org
BUG=595137
==========

to

==========
Track lastTextNode during rebuildLayoutTree.

We keep track of last seen text node for more efficient whitespace
re-attachment. When style recalc and layout tree building was split,
the text node is still tracked during recalc, stored in a hash map, and
retreived when needed during layout tree building.

However, the text nodes are also traversed during layout tree building
so that we can track the nodes during that phase instead.
StyleReattachData is removed and this CL reverts back to using the
m_nonAttachedStyle map for ComputedStyle.

The comment about reversed traversal of children for avoiding n^2
performance is moved to rebuildChildrenLayoutTrees() since that's where
the issue is. We should be able to do the child recalc first-to-last
now if we want to.

R=nainar@chromium.org,esprehn@chromium.org
BUG=595137

Review-Url: https://codereview.chromium.org/2740823005
Cr-Commit-Position: refs/heads/master@{#456047}
Committed:
https://chromium.googlesource.com/chromium/src/+/af8b67666d6c89aec9abebe7df21...
==========

[commit-bot: I haz the power, 2017-03-10 12:37:28]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/af8b67666d6c89aec9abebe7df21...

[Bugs Nash, 2017-03-12 20:35:07]

This is fantastic! Good work Rune