Highlight ToolbarIconContainerView when hovered

Changes the detection mechanism for the ToolbarIconContainerView
highlight border so that it is active when either:

* The container is mouse hovered but the main view is not.
* Any child view has focus.
* Any child view is in the pressed state.

Bug: chromium:932818, chromium:943702
Change-Id: I388a4b78a43ddd05b3dd2623321f92938110ba0f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1674629
Reviewed-by: Siyu An <siyua@chromium.org>
Commit-Queue: Peter Boström <pbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#671899}
3 files changed