Add chrome sync tests to the GN build.

components/sessions/BUILD.gn

 # Copyright 2014 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.
 
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 # TODO(rohitrao): sessions_core is defined as a source_set because it declares a
 # static function that it does not define.  This prevents it from linking as a
@@ skipping 30 matching lines @@
     "//ui/base",
     "//ui/gfx",
     "//url",
   ]
 
   if (!is_android || !is_android_webview_build) {
     deps += [ "//sync" ]
   }
 }
 
-static_library("test_support") {
+source_set("test_support") {
   testonly = true
   sources = [
     "serialized_navigation_entry_test_helper.cc",
     "serialized_navigation_entry_test_helper.h",
   ]
 
   deps = [
+    ":sessions_core",
     "//skia",
     "//testing/gtest",
   ]
 
   if (!is_android || !is_android_webview_build) {
     deps += [ "//sync" ]
   }
 
   if (!is_android && !is_ios) {
     sources += [
@@ skipping 34 matching lines @@
     ]
     deps = [
       ":sessions_content",
       "//base/test:test_support",
       "//testing/gtest",
       "//third_party/protobuf:protobuf_lite",
     ]
   }
 }