Convert some GN test support targets to static libs.

ui/base/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.
 
 import("//build/buildflag_header.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
@@ skipping 593 matching lines @@
         "clipboard/clipboard_aura.h",
       ]
     }
   }
 
   if (is_android || is_ios) {
     sources -= [ "device_form_factor_desktop.cc" ]
   }
 }
 
-source_set("test_support") {
+static_library("test_support") {
   testonly = true
   sources = [
     "test/material_design_controller_test_api.cc",
     "test/material_design_controller_test_api.h",
     "test/ui_controls.h",
     "test/ui_controls_aura.cc",
     "test/ui_controls_internal_win.cc",
     "test/ui_controls_internal_win.h",
     "test/ui_controls_mac.mm",
     "test/ui_controls_win.cc",
@@ skipping 324 matching lines @@
 if (is_mac) {
   mac_framework_bundle("ui_unittests_framework") {
     testonly = true
     deps = [
       "//ui/resources:ui_test_pak_bundle_data",
     ]
     info_plist = "test/framework-Info.plist"
     output_name = "ui_unittests Framework"
   }
 }