[iOS] Separate flags for copied text/images in omnibox and elsewhere

This CL separates the one "copied text behavior" flag into 3. One
controls the copied text suggestion in the omnibox, one controls the
copied image suggestion in the omnibox, and the last controls all
copied content behavior elesewhere (omnibox long-press, search
accelerator menu)

Bug: 913958
Change-Id: I36ae3266ce03c657697777b9c43b0ba206bc677b
Reviewed-on: https://chromium-review.googlesource.com/c/1402754
Commit-Queue: Robbie Gibson <rkgibson@google.com>
Reviewed-by: Mark Cogan <marq@chromium.org>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621534}
14 files changed