Remove content_packaged_services

This removes content_packaged_services entirely, switching instead to a
direct delegate interface on Service Manager, allowing the Content
layer to directly field service process launching requests.

Follow-up CLs will further simplify in- and out-of-process service
configuration, and this is ultimately a step towards migrating process
launch out of Content and into Service Manager and removing other things
like content::ServiceManagerConnection.

Bug: 781334,895615
Change-Id: I9243eb24b0152c2b353909718d8d3de223a6af9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1604203
Commit-Queue: Ken Rockot <rockot@google.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Reviewed-by: Oksana Zhuravlova <oksamyt@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663141}
66 files changed