The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c6166c42eb321f985ae916bda6c9dde76891e244

commit c6166c42eb321f985ae916bda6c9dde76891e244
Author: Naoki Fukino <fukino@chromium.org>
Date: Wed Jul 19 05:34:20 2017

Files app: Move a button to share file in Google Drive to share options menu.

This CL moves the share function for Google Drive files from a toolbar button
to share options menu.
As a result, the share options menu should be shown when 1) share function for
Google Drive is enabled for the selected file or 2) there is at least one
non-open action for the selected file.

Bug:  741553 
Change-Id: I5066203e7a5809e1db048f1c72d2ab9fe3a8cfd6
Reviewed-on: https://chromium-review.googlesource.com/575299
Reviewed-by: Tatsuhisa Yamaguchi <yamaguchi@chromium.org>
Commit-Queue: Naoki Fukino <fukino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487765}
[modify] https://crrev.com/c6166c42eb321f985ae916bda6c9dde76891e244/ui/file_manager/file_manager/foreground/css/file_manager.css
[delete] https://crrev.com/860b3978205e2fbef3f89c2ee586ce627a41164a/ui/file_manager/file_manager/foreground/images/files/ui/2x/person_add_white.png
[delete] https://crrev.com/860b3978205e2fbef3f89c2ee586ce627a41164a/ui/file_manager/file_manager/foreground/images/files/ui/person_add_white.png
[modify] https://crrev.com/c6166c42eb321f985ae916bda6c9dde76891e244/ui/file_manager/file_manager/foreground/js/file_tasks.js
[modify] https://crrev.com/c6166c42eb321f985ae916bda6c9dde76891e244/ui/file_manager/file_manager/foreground/js/task_controller.js
[modify] https://crrev.com/c6166c42eb321f985ae916bda6c9dde76891e244/ui/file_manager/file_manager/main.html
[modify] https://crrev.com/c6166c42eb321f985ae916bda6c9dde76891e244/ui/file_manager/integration_tests/file_manager/share_dialog.js
[modify] https://crrev.com/c6166c42eb321f985ae916bda6c9dde76891e244/ui/file_manager/integration_tests/file_manager/tab_index.js

This issue is partially fixed. 
1. The part fixed is - Share button is moved to share options menu for a selected file.
2. The part not fixed - at least one non-open action for the selected file. Sometimes share options menu doesn't appear. Refer  issue 747607 .

Re: #4, could you verify this on 1) in your list?
I'll keep track of the  issue 2 ) on  issue 747607  as a separate issue.

Verified on M61 (Chrome OS 9765.16.0, 61.0.3163.30 dev build).