When we integrated Google Drive files to the launcher, we excluded local files to avoid privacy concerns.
https://bugs.chromium.org/p/chromium/issues/detail?id=474291

We should revisit it and go through the launch review by taking care of the privacy.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/571c8566c2eb0aa945c5b44bef061c26c953f7f6

commit 571c8566c2eb0aa945c5b44bef061c26c953f7f6
Author: Naoki Fukino <fukino@chromium.org>
Date: Tue Dec 26 10:14:58 2017

Show files/directories from Downloads volume in launcher search resutls.

This change adds local entries to the result of launcher search.
Finding local entries is done by recursive reads for the Downloads
volume in JS side. Now that both foreground and background do the
similar recursive reads, the common implementation is moved from
LocalSearchContentScanner to a common util function.
As a part of this change, I added a logic to prefer files which have
the search query as their prefixes in reply to omri's request.

Bug:  773497 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I22921e6c141aa9014198446ea8a562c6b5154fbf
Reviewed-on: https://chromium-review.googlesource.com/842365
Commit-Queue: Naoki Fukino <fukino@chromium.org>
Reviewed-by: Tatsuhisa Yamaguchi <yamaguchi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526189}
[modify] https://crrev.com/571c8566c2eb0aa945c5b44bef061c26c953f7f6/ui/file_manager/file_manager/background/js/launcher_search.js
[modify] https://crrev.com/571c8566c2eb0aa945c5b44bef061c26c953f7f6/ui/file_manager/file_manager/common/js/util.js
[modify] https://crrev.com/571c8566c2eb0aa945c5b44bef061c26c953f7f6/ui/file_manager/file_manager/foreground/js/directory_contents.js

Issue 753970 has been merged into this issue.

Verified on M65 dev build (10323.2.0, 65.0.3325.11) cave device.