[Feed] Import feed@4dedff6189bbd8f3dc594ba3e2159ccdf929359a

This patch rolls the Feed library forward to revision:
4dedff6189bbd8f3dc594ba3e2159ccdf929359a

This patch also fixes the BUILD.gn:
* adds missing files.
* reduces the number of targets, to simplify management.

Because none of the code is presently used, it has no impact on
DEX sizes. There is a minor impact on resources size (1kB).

Change-Id: Idcd00ea084c137f2b9d9f4bf46ea1051930b1b0c
Reviewed-on: https://chromium-review.googlesource.com/952185Reviewed-by: agrieve <agrieve@chromium.org>
Reviewed-by: Pavel Yatsuk <pavely@chromium.org>
Commit-Queue: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541548}

DEPS

@@ -151,7 +151,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.
-  'feed_revision': '5ebe38905c1a1d09e39a22cfb8ae59531553b65a',
+  'feed_revision': '4dedff6189bbd8f3dc594ba3e2159ccdf929359a',
 }
 
 # Only these hosts are allowed for dependencies in this DEPS file.

third_party/feed/README.chromium

@@ -2,7 +2,7 @@ Name: Feed
 Short name: feed
 URL: https://chromium.googlesource.com/feed
 Version: 0
-Revision: 5ebe38905c1a1d09e39a22cfb8ae59531553b65a
+Revision: 4dedff6189bbd8f3dc594ba3e2159ccdf929359a
 License: Apache 2.0
 License File: LICENSE
 Security Critical: yes