Convert test_support source sets to static libs

components/dom_distiller/core/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.
 
 # GYP version: components/dom_distiller.gypi:dom_distiller_core
 source_set("core") {
   sources = [
     "article_attachments_data.cc",
     "article_attachments_data.h",
     "article_distillation_update.cc",
@@ skipping 70 matching lines @@
   if (is_android) {
     sources += [
       "dom_distiller_service_android.cc",
       "dom_distiller_service_android.h",
     ]
     deps += [ ":jni_headers" ]
   }
 }
 
 # GYP version: components/dom_distiller.gypi:dom_distiller_test_support
-source_set("test_support") {
+static_library("test_support") {
   testonly = true
   sources = [
     "dom_distiller_test_util.cc",
     "dom_distiller_test_util.h",
     "fake_distiller.cc",
     "fake_distiller.h",
     "fake_distiller_page.cc",
     "fake_distiller_page.h",
     "test_request_view_handle.h",
   ]
@@ skipping 64 matching lines @@
 
   generate_jni("jni_headers") {
     sources = [
       "../android/java/src/org/chromium/components/dom_distiller/core/DistilledPagePrefs.java",
       "../android/java/src/org/chromium/components/dom_distiller/core/DomDistillerService.java",
       "../android/java/src/org/chromium/components/dom_distiller/core/DomDistillerUrlUtils.java",
     ]
     jni_package = "dom_distiller_core"
   }
 }