Files.app: Clear the sync message after completion.

Previously, if the sync took a time, the message never disappeared.
This was caused by drop of the callback() invokation in AsyncUtil.Queue.
This CL fixes it.

BUG=340419
TEST=manually

Review URL: https://codereview.chromium.org/153663002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248864 0039d316-1c4b-4281-b951-d872f2087c98
Disable RealServiceProcessControlBrowserTest.* and remove deppendency of browser_tests on chrome.

TBR=thestig
BUG=340563

Review URL: https://codereview.chromium.org/153553002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248865 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248864
SVN changes up to revision 248865