The number of undo operation owners is small (and usually one), so save memory by switching to ArrayMap. Bug: 19332904 Change-Id: Ic32cd49c292db2eaab1739cea8e8e518e68bd826
The number of undo operation owners is small (and usually one), so save memory by switching to ArrayMap. Bug: 19332904 Change-Id: Ic32cd49c292db2eaab1739cea8e8e518e68bd826