[iOS] Make the TableView's empty view scrollable

This CL adds a scroll view containing the text displayed when the table
view is empty. It allows the user to scroll the text if the font size
used is big.
As the safe area insets aren't propagated to the empty view, this is
using dummy view to fake the safe area insets in the scroll view.

Bug: 893535
Change-Id: I63b658c1bc9d5cacdb4e86d201a2bb2ca7621a96
Reviewed-on: https://chromium-review.googlesource.com/c/1353941
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Kurt Horimoto <kkhorimoto@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613087}
3 files changed