[iOS][coordinator] Modernize Omnibox Popup Coordinator.

This CL modernizes the OmniboxPopupCoordinator
 - to use |browser| in the initializer,
 - to remove the public property for  dispatcher, webstatelist and
browserstate,
 - to use self.browser to get browserstate, webstatelist and dispatcher
values.

This CL includes migration to ChromeCoordinator as a superclass.

Bug: 1029346, 1048423
Change-Id: Id99b8197d23cbb9d0b16e9a35b096a9b91213562
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2068598
Reviewed-by: Mark Cogan <[email protected]>
Commit-Queue: Nazerke Kalidolda <[email protected]>
Cr-Commit-Position: refs/heads/master@{#743899}
5 files changed