Add updater targets to check targets.

Bug: 1054807
Fixed: 1054807
Change-Id: Ib7edaa00d05a68c4ca6b7a2fbe563fe09e25de83
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2068054
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743835}

.gn

@@ -236,6 +236,7 @@ check_targets = [
   "//chrome/test/chromedriver",
   "//chrome/third_party/*",
   "//chrome/tools/*",
+  "//chrome/updater/*",
   "//chrome/utility/*",
 
   "//chromecast/*",