chrome_extensions.js: 8c8758d268411a685b187a9942077c604a8e11c3 -> 5a25bfc4e006f1a965d362e27938611242908acd

 - Delete third_party/closure_compiler/externs/web_animations.js and
   all references to it. No longer needed since a better version of these
   externs is distributed within compiler.jar itself.
 - Fix newly found JSC_HIDDEN_INTERFACE_PROPERTY_MISMATCH, as a result of the
   interface checking overhaul at [1]
 - Fix/suppress newly found JSC_CONSTANT_PROPERTY_REASSIGNED_VALUE errors.

The latest version of chrome_extensions.js contains a fix needed by PDF Viewer.

[1] https://github.com/google/closure-compiler/commit/86acbd5e3ec78f08a1804df5f1efbea129d29c0e

Bug: 1011585
Change-Id: Ic7682834da9cfb75990d82fd8d34d3325d0a6bc3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1842626Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Auto-Submit: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708089}