[ios] Adds code for Omaha and the upgrade center.

ios/chrome/browser/upgrade/BUILD.gn

+# Copyright 2016 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("upgrade") {
+  sources = [
+    "upgrade_center.h",
+    "upgrade_center.mm",
+    "upgrade_recommended_details.h",
+  ]
+  deps = [
+    "//base",
+    "//components/infobars/core",
+    "//components/version_info",
+    "//ios/chrome/app/strings",
+    "//ios/chrome/browser",
+    "//ios/chrome/browser/ui/commands",
+    "//ios/chrome/browser/ui/infobars:resources",
+    "//ios/web",
+    "//net",
+    "//ui/base",
+    "//ui/gfx",
+    "//url",
+  ]
+  libs = [ "UIKit.framework" ]
+}
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [
+    "upgrade_center_unittest.mm",
+  ]
+  deps = [
+    ":upgrade",
+    "//base",
+    "//testing/gtest",
+  ]
+}