[iOS] Using item type in the UISwitch for SettingsSwitchCell

The item type is set in the UISwitch.tag. When the UISwitch action is
called, the item type (using the UISwitch.tag) is used to find the item.
The GoogleServicesSettingsViewController needs the item to call its
service delegate when the user taps an UISwitch.

Bug: 914059
Change-Id: Ie8c6b9cb8f2dbde1c123065bd8ac8d64c94c7de7
Reviewed-on: https://chromium-review.googlesource.com/c/1474758
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#633146}
2 files changed