Error at `compile-santa-api-service` task

[NewGyu]

Hi, I'm trying to build on my machine(Ubuntu 16.04).

$ uname -a
Linux newgyu-XPS-13-9350 4.4.0-47-generic #68-Ubuntu SMP Wed Oct 26 19:39:52 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

However, the following error occurred.

/var/santa # gulp dist
[16:20:50] Using gulpfile /var/santa/gulpfile.js
[16:20:50] Starting 'rm-dist'...
[16:20:50] Starting 'sass'...
[16:20:50] Starting 'compile-scenes'...
[16:20:50] Starting 'compile-santa-api-service'...
[16:20:50] Starting 'i18n_index'...
[16:20:50] Finished 'rm-dist' after 241 ms
[16:21:01] Finished 'i18n_index' after 10 s
[16:21:22] Finished 'sass' after 32 s

stream.js:74
      throw er; // Unhandled stream error in pipe.
      ^
Error: components/web-animations-utils/externs-next.js:86: WARNING - variable AnimationTimeline redefined with type function (this:AnimationTimeline): ?, original definition at third_party/externs/web-animations-old.js:23 with type function (new:AnimationTimeline): ?
var AnimationTimeline = function() {};
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I tried to remove rm /var/santa/third_party/externs/web-animations-old.js . Then several warnings occurred, but the task succeeded.

Is web-animations-old.js necessary?
If I should fix web-animations-old.js please tell me how to fix it.

[samthor]

We'll be releasing the 2016 version of Santa Tracker next year, which will resolve this issue.