Closure compiler has not been rolled to a new version for a fairly long time, since Aug 2017, see [1]. As part of updating iron-list to its latest version ( issue 815009 ), need to also roll the compiler to pick up latest Polymer 2 externs.
Doing so revealed a bunch new (legit) type errors, which indicates that the compiler got smarter and more strict. These errors need to be fixed before rolling the new version.
Also, as part of fixing https://github.com/google/closure-compiler/issues/1189, chrome.js externs are now not included by default, which requires tweaking our own roll_closure_compiler script (and some more).
Original WIP CL from scottchen@ is at [2]. I am taking over this task while Scott is OOO.
[1] https://chromium-review.googlesource.com/592719
[2] https://chromium-review.googlesource.com/c/chromium/src/+/592719
Note to self: We should be rolling Closure compiler periodically, so that updates are not as involved as this one. Also per dbeam@, he used to roll about once a month in the past.
Comment 1 by dpa...@chromium.org
, Apr 10 2018