GitLab

1) Qualify drive label selector in test_util.js to just elements under the drive tree. And (re-)add the drive icon to the Cloud Import drop down.

2) Don't auto-hide cloud-import buttons when disabled...(fyi, they're disabled when in scanning and importing modes...we want the user to see them).

3) Format values on details panel in a human friendly way.

BUG=420680
TEST=browser_test: *FileManager*

Review URL: https://codereview.chromium.org/902253003

Cr-Commit-Position: refs/heads/master@{#315309}