[App Management] Implement the OpenNativeSettings App Service method for extensions.

This CL implements the OpenNativeSettings method for the ExtensionApps
App Service publisher. For now, it supports two types of extensions:
for hosted apps, it opens the corresponding site settings page; for the
Chrome Apps which appear on the chrome://extensions page, it opens the
extensions detail page for that app.

Bug: 906508
Change-Id: I6f5cee42d9f909e3c24bbecd91b5fe8d37923338
Reviewed-on: https://chromium-review.googlesource.com/c/1405112
Commit-Queue: Reka Norman <rekanorman@google.com>
Reviewed-by: Nigel Tao <nigeltao@chromium.org>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: calamity <calamity@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622381}
18 files changed