commit 592eb5df9a5d469cdacb48559945e0dfdd7abb10
author sigbjornf <sigbjornf@opera.com> Fri Jan 08 13:40:20 2016
committer Commit bot <commit-bot@chromium.org> Fri Jan 08 13:41:07 2016
tree fe4686baca8765045cc30eb8d9983c8f49b19b54
parent f94944ad723e8a0cbee71258960394d17f32adef

Handle some failing DocumentOrderedMap ID lookups across tree removals.

r366066's attempt to better handle failing DocumentOrderedMap lookups
while an element is being removed from a tree with duplicate IDs, didn't
accommodate all cases where the document map might end up being consulted.

Widen the assert and have it scope over node removals; should the unlikely
case happen, recognize that the tree is in a transitory state and allow
the lookup to quietly fail.

TBR=esprehn
BUG=571351

Review URL: https://codereview.chromium.org/1555653002

Cr-Commit-Position: refs/heads/master@{#368321}