Don't make unnecessary copy of ChildToParentMap

Don't make unnecessary copy of ChildToParentMap

The right branch of the ternary was an rvalue, so the entire ternary operator made a copy of the child to parent map. This is expensive and is unnecessary.

CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Committed: https://crrev.com/84b141c3e588831b4d7436fc67068ec121372b04
Cr-Commit-Position: refs/heads/master@{#333102}

[jbauman, 2015-06-05 13:18:47]

jbauman@chromium.org changed reviewers:
+ vmpstr@chromium.org

[enne (OOO), 2015-06-05 17:51:04]

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

[enne (OOO), 2015-06-05 17:51:04]

The CQ bit was checked by enne@chromium.org

[enne (OOO), 2015-06-05 17:51:04]

lgtm

[commit-bot: I haz the power, 2015-06-05 17:51:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1156303013/1

[commit-bot: I haz the power, 2015-06-05 18:54:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-05 19:06:21]

Patchset 1 (id:??) landed as
https://crrev.com/84b141c3e588831b4d7436fc67068ec121372b04
Cr-Commit-Position: refs/heads/master@{#333102}