GitLab

Previously if drive sync over cellular network is disabled, pinning a drive file
is pending without notificaiton.

This CL lets Files.app show the notifiction.

BUG=279476
TEST=DriveSpecific/FileManagerBrowserTest.Test/4

Review URL: https://codereview.chromium.org/676653002

Cr-Commit-Position: refs/heads/master@{#302063}