Componentize AutofillMetricsTest.

The componentization is straightforward, following the patterns of other
Autofill test componentizations.

BUG=303083
R=isherman@chromium.org

Review URL: https://codereview.chromium.org/177013005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255908 0039d316-1c4b-4281-b951-d872f2087c98
[SyncFS] Drop default priority version of SyncTaskManager::ScheduleTask

* Drop SyncTaskManager::Schedule{,Sync}Task
* Rename Schedule{,Sync}TaskAtPriority to Schedule{,Sync}Task

BUG=344769

Review URL: https://codereview.chromium.org/190663004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255909 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255909