Files.app: Hide loading indicator on launch.
Files.app: Hide loading indicator on launch.

BUG=475377
TEST=manually
TBR=yawano@chromium.org

Review URL: https://codereview.chromium.org/1071033003

Cr-Commit-Position: refs/heads/master@{#324397}
(cherry picked from commit 5f6ee174b82c3c15ac85ef06b9e3ee0e6563f735)

Review URL: https://codereview.chromium.org/1082193002

Cr-Commit-Position: fe94940391158563b8e4cf7888f93321f554af93@{#81}
Cr-Branched-From: 9fdd9ec11ee753dedeffe15e7e822b13445dc287@{#323860}

fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk