Turn the utility process image decoder into a Mojo service.

services/test/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("metro_utils") {
+source_set("run_all_unittests") {
+  testonly = true
+
+  sources = [
+    "services_unittest_main.cc",
+  ]
+
   deps = [
     "//base",
-    "//chrome/installer/util",
-  ]
-  sources = [
-    "metro_chrome_win.cc",
-    "metro_chrome_win.h",
+    "//base/test:test_support",
+    "//content/test:test_support",
+    "//mojo/environment:chromium",
   ]
 }