Notify the counter code about layout object removals BEFORE removing.

Notify the counter code about layout object removals BEFORE removing.

This makes it possible to mark relevant objects for layout. Cannot mark
unrooted subtrees for layout.

Additionally, only notify when told to do so by the caller. Renamed the method
to layoutObjectSubtreeWillBeDetached(), inspired by its
layoutObjectSubtreeAttached() counterpart.

For the sake of consistency, also only call layoutObjectSubtreeAttached() when
actually told to notify.

BUG=492490
R=dsinclair@chromium.org,eae@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196505

[mstensho (USE GERRIT), 2015-06-04 07:19:51]

mstensho@opera.com changed reviewers:
+ schenney@chromium.org

[mstensho (USE GERRIT), 2015-06-04 07:19:52]

This is a counter-proposal (no pun intended) to
https://codereview.chromium.org/1144423007/

Usually when the counter code marked counter objects for layout after an
ancestor had been removed, it worked just fine, at least as long as the
containing block of the counter object was still to be found in the unrooted
subtree (so that we'd have a beautifully marked containing block chain when the
subtree was reattached later on). But that could easily not be the case if
absolutely positioned objects were involved (like in the TC)...

[esprehn, 2015-06-04 08:22:30]

esprehn@chromium.org changed reviewers:
+ esprehn@chromium.org

[esprehn, 2015-06-04 08:22:31]

That notify flag always seemed kind of sketchy, someday we should get rid of it.
:/

lgtm

[dsinclair, 2015-06-04 13:36:04]

The CQ bit was checked by dsinclair@chromium.org

[dsinclair, 2015-06-04 13:36:05]

lgtm

[commit-bot: I haz the power, 2015-06-04 13:36:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1143323011/1

[commit-bot: I haz the power, 2015-06-04 14:04:57]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196505