This should be do-able now that  issue 908299  is complete.

Nicked!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d96084d3ac04efa1c068478c46bb54209fc5d1d4

commit d96084d3ac04efa1c068478c46bb54209fc5d1d4
Author: Noel Gordon <noel@chromium.org>
Date: Wed Nov 28 01:44:41 2018

Closure compile file_operation_manager_unittest

 - remove file_operation_manager_unittest.html
 - add BUILD rules to auto-generate and compile this unittest
 - define mockChrome and install it in unittest Setup()
 - fix Closure compile errors

No change in test behavior, no new tests.

Bug:  907967 
Change-Id: I523218dd179c5e9b0ae55b81d4a5480eea279f8c
Reviewed-on: https://chromium-review.googlesource.com/c/1352115
Reviewed-by: Stuart Langley <slangley@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611501}
[modify] https://crrev.com/d96084d3ac04efa1c068478c46bb54209fc5d1d4/chrome/browser/chromeos/file_manager/file_manager_jstest.cc
[modify] https://crrev.com/d96084d3ac04efa1c068478c46bb54209fc5d1d4/ui/file_manager/file_manager/background/js/BUILD.gn
[delete] https://crrev.com/c362c846e8f3691a869993c67dae583af16cb78a/ui/file_manager/file_manager/background/js/file_operation_manager_unittest.html
[modify] https://crrev.com/d96084d3ac04efa1c068478c46bb54209fc5d1d4/ui/file_manager/file_manager/background/js/file_operation_manager_unittest.js

Marked fixed.