DevTools: avoid using stale front-end node ids.

DevTools: avoid using stale front-end node ids.

When a node is removed and then re-added to the document,
the back-end node id remains the same and the front-end id
is new. This means that if we keep resolved front-end nodes,
we should check if these still exist and re-resolve the ids
to new nodes if these are detached and re-attached to the document.

BUG=
R=vsevik@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169526

[vsevik, 2014-03-14 10:03:26]

lgtm

[caseq, 2014-03-14 13:32:01]

The CQ bit was checked by caseq@chromium.org

[commit-bot: I haz the power, 2014-03-14 13:32:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/caseq@chromium.org/195813010/20001

[commit-bot: I haz the power, 2014-03-14 14:00:42]

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

[commit-bot: I haz the power, 2014-03-14 14:00:43]

Try jobs failed on following builders:
  tryserver.blink on mac_blink_rel

[caseq, 2014-03-18 16:03:59]

The CQ bit was checked by caseq@chromium.org

[commit-bot: I haz the power, 2014-03-18 16:04:11]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/caseq@chromium.org/195813010/40001

[commit-bot: I haz the power, 2014-03-18 16:05:44]

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

[commit-bot: I haz the power, 2014-03-18 16:05:44]

Try jobs failed on following builders:
  tryserver.blink on mac_blink_rel

[caseq, 2014-03-19 07:53:26]

Committed patchset #2 manually as r169526 (presubmit successful).