Create a skeleton updater main for Windows.

This change builds an executable program on Windows, which returns
a hardcoded value. The value is tested by a unit test.

The updater executable contains a valid resource file and manifest.

An upcoming change will hook the test with the test bots.
Then, another change will implement a similar function for macOS.

Bug: 925489
Change-Id: Id97f4740a2cd9e3d21c00e631a8e03c19757468a
Reviewed-on: https://chromium-review.googlesource.com/c/1437266
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Sorin Jianu <sorin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#627053}

diff --git a/BUILD.gn b/BUILD.gn
index b3febd5..1c2b64e 100644
--- a/BUILD.gn
+++ b/BUILD.gn

@@ -67,6 +67,7 @@
     "//base:base_perftests",
     "//base:base_unittests",
     "//chrome/installer",
+    "//chrome/updater",
     "//net:net_unittests",
     "//skia:skia_unittests",
     "//sql:sql_unittests",