Omnibox: Steady State Elisions - Fix some model vs. view logic division

Chrome has a bug where when the user focuses the Omnibox via Ctrl+L or
F6, sometimes the page action icons disappear.

This is because OmniboxEditModel::Unelide currently lacks a necessary
check. This CL adds that check and adds a test to verify that.

It moves some logic that existed in the OmniboxViewViews over to
OmniboxEditModel and de-duplicates some logic.

Bug: 921777
Change-Id: Ifed90d61e5b820eaaf16b41ba62a13eac73b10ff
Reviewed-on: https://chromium-review.googlesource.com/c/1410016
Commit-Queue: Tommy Li <tommycli@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623482}
4 files changed