Pass account_id and scope_set to CreateAttachmentService via UserShare.
Add scope set to SyncCredentials so it can be used by AttachmentUploader
and AttachmentDownloader.
Upgrade SynCredentials from struct to simple class with accessors.
Populate UserShare's account id and scope set using SyncCredentials.
Remove account id and scope set from ProfileSyncComponentsFactoryImpl
because PSCFI lives across signin/signout events. Instead, get this
stuff from UserShare.
BUG=
Review URL: https://codereview.chromium.org/
360033005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@280831 0039d316-1c4b-4281-b951-d872f2087c98