[SendTabToSelf] Add omnibox icon animation

- The icon will slides in with "Send" label when the valid url is
highlighted at the first time.
- The icon will slides out and remain an icon to the right side of
the omnibox.
- The icon will remain if the url is valid, even after the sharing
action of the user.

Bug: 950388
Change-Id: Icbe7bc5806d6bc8e38c62a8eba9794b2900db16e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1555501
Commit-Queue: Tina Wang <tinazwang@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: sebsg <sebsg@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654120}
18 files changed