Add the Clean toolbar to ios/chrome

This CL adds the Toolbar objects (coordinator/mediator/ViewController)
created in ios/clean in ios/chrome/browser/ui/toolbar/clean.
It will allow to modify and use them in chrome. For now those objects
are not used in ios/chrome, to allow an easier review.
All the content specific to ios/clean is removed, except the dispatcher
protocols which are adapted to the ones used in ios/chrome.

The classes are duplicated, with the one in ios/clean prefixed with
"Clean". The constants and other utility files are moved.

Having this code checkout in ios/chrome will allow to work on them more
easily than having to import them file by file every time we need to
use one.

Bug: 784372
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ia5eb513198b32a1d2f93603c36884c90d04cbbaf
Reviewed-on: https://chromium-review.googlesource.com/766370
Reviewed-by: Mark Cogan <[email protected]>
Commit-Queue: Gauthier Ambard <[email protected]>
Cr-Commit-Position: refs/heads/master@{#516284}
39 files changed