GitLab

 - remove file_operation_handler_unittest.html
 - add BUILD rules to auto-generate and compile this unittest
 - document, add Closure @type's, and auto-format the unittest
 - fix Closure compile errors

No change in test behavior, no new tests.

Bug: 910774
Change-Id: Ie91e8ac6951821af05cd5c8482b7be7ae2c3b04f
Reviewed-on: https://chromium-review.googlesource.com/c/1356726
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612990}