cf5cdea808
This is a step towards separating the element map implementations. Change-Id: Iaf8cee48bd0c127a981b1661773d9036b419fecf Reviewed-on: https://dart-review.googlesource.com/75300 Reviewed-by: Stephen Adams <sra@google.com> Commit-Queue: Johnni Winther <johnniwinther@google.com>