NOTE: this is a partial rollback.  The mapFn argument change was fine.
NOTE: this is a partial rollback.  The mapFn argument change was fine.

Automated g4 rollback of changelist 126131903.

*** Reason for rollback ***

It turns out that Array.from doesn't take an Iterator after all.

*** Original change description ***

Fix Array.from extern to (1) allow Iterator and (2) remove incorrect third argument in mapFn.

***
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=126469203

shantanusharma/closure-compiler,google/closure-compiler,vobruba-martin/closure-compiler,Medium/closure-compiler,Dominator008/closure-compiler,monetate/closure-compiler,nawawi/closure-compiler,GerHobbelt/closure-compiler,vobruba-martin/closure-compiler,tiobe/closure-compiler,vobruba-martin/closure-compiler,monetate/closure-compiler,nawawi/closure-compiler,mprobst/closure-compiler,monetate/closure-compiler,google/closure-compiler,ChadKillingsworth/closure-compiler,Yannic/closure-compiler,anomaly/closure-compiler,anomaly/closure-compiler,nawawi/closure-compiler,shantanusharma/closure-compiler,Dominator008/closure-compiler,Medium/closure-compiler,Pimm/closure-compiler,MatrixFrog/closure-compiler,tdelmas/closure-compiler,brad4d/closure-compiler,tdelmas/closure-compiler,brad4d/closure-compiler,mprobst/closure-compiler,brad4d/closure-compiler,tiobe/closure-compiler,MatrixFrog/closure-compiler,Yannic/closure-compiler,LorenzoDV/closure-compiler,tdelmas/closure-compiler,tiobe/closure-compiler,anomaly/closure-compiler,MatrixFrog/closure-compiler,Yannic/closure-compiler,tdelmas/closure-compiler,mprobst/closure-compiler,shantanusharma/closure-compiler,ChadKillingsworth/closure-compiler,GerHobbelt/closure-compiler,Dominator008/closure-compiler,GerHobbelt/closure-compiler,MatrixFrog/closure-compiler,google/closure-compiler,anomaly/closure-compiler,vobruba-martin/closure-compiler,Pimm/closure-compiler,monetate/closure-compiler,Pimm/closure-compiler,Medium/closure-compiler,ChadKillingsworth/closure-compiler,google/closure-compiler,mprobst/closure-compiler,nawawi/closure-compiler,ChadKillingsworth/closure-compiler,Yannic/closure-compiler,GerHobbelt/closure-compiler,LorenzoDV/closure-compiler,tiobe/closure-compiler,LorenzoDV/closure-compiler,shantanusharma/closure-compiler