Revert 246120 "Implements the Synced Notifications Welcome Toast."

> Implements the Synced Notifications Welcome Toast.
> 
> The first notification for synced notifications will
> now generate a normal notification explaining the new
> service.
> 
> This does not yet implement click-to-disable or have
> proper resources.
> 
> BUG=315248
> 
> Review URL: https://codereview.chromium.org/140053003

TBR=dewittj@chromium.org

Review URL: https://codereview.chromium.org/143903009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246137 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246137