Add support for building "ios_chrome_unittests" with gn.

ios/chrome/common/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("common") {
   sources = [
-    "win/cloud_print_utils.cc",
-    "win/cloud_print_utils.h",
+    "channel_info.h",
+    "channel_info.mm",
+    "string_util.h",
+    "string_util.mm",
   ]
 
   deps = [
     "//base",
+    "//components/version_info",
+    "//ios/chrome/common/app_group:main_app",
+  ]
+
+  libs = [
+    "CoreGraphics.framework",
+    "Foundation.framework",
   ]
 }
-
-source_set("install_utils") {
-  sources = [
-    "win/install_utils.cc",
-    "win/install_utils.h",
-  ]
-
-  deps = [
-    ":common",
-    "//base",
-  ]
-}