Convert test_support source sets to static libs

components/autofill/content/renderer/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.
 
 static_library("renderer") {
   sources = [
     "autofill_agent.cc",
     "autofill_agent.h",
     "form_autofill_util.cc",
     "form_autofill_util.h",
@@ skipping 30 matching lines @@
     "//skia",
     "//third_party/WebKit/public:blink",
     "//third_party/re2",
     "//ui/base",
   ]
 
   # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 }
 
-source_set("test_support") {
+static_library("test_support") {
   testonly = true
   sources = [
     "test_password_autofill_agent.cc",
     "test_password_autofill_agent.h",
     "test_password_generation_agent.cc",
     "test_password_generation_agent.h",
   ]
 
   public_deps = [
     ":renderer",
@@ skipping 12 matching lines @@
     "renderer_save_password_progress_logger_unittest.cc",
   ]
 
   deps = [
     ":test_support",
     "//components/autofill/content/common",
     "//ipc:test_support",
     "//testing/gtest",
   ]
 }