[Extensions] Enable action.setIcon and add end-to-end tests

Enable the action.setIcon function (define the extension function,
add histogram values, and add custom bindings), and add a parameterized
end-to-end test for setting the icon from both a local path and
canvas image data.

Bug: 893373
Change-Id: I249d6e980469fe3af2c541db92bba09b2d87ce03
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1658421
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672167}
10 files changed