Implement refreshing logic in Files app.
This CL adds an implementation for the refresh button for volumes which do not
support file watching.
Since refreshing is often fast and seems like not doing anything, a blink method
on the spinner controller has been added, so the spinner always shows for at
least one second when refreshing, so users have feedback that the refreshing
is completed.
TEST=Tested manually.
BUG=501864
Review URL: https://codereview.chromium.org/
1222563005
Cr-Commit-Position: refs/heads/master@{#337573}