Control TaskScheduler initialization params in renderers via field trial.

components/task_scheduler_util/BUILD.gn

 # Copyright 2016 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("browser") {
   sources = [
     "browser/initialization.cc",
     "browser/initialization.h",
   ]
 
   deps = [
     ":common",
     "//base",
     "//base:base_static",
   ]
 }
 
+static_library("renderer") {
+  sources = [
+    "renderer/initialization.cc",
+    "renderer/initialization.h",
+  ]
+
+  deps = [
+    ":common",
+    "//base",
+  ]
+}
+
 static_library("common") {
   sources = [
     "common/variations_util.cc",
     "common/variations_util.h",
   ]
 
   deps = [
     "//base",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "common/variations_util_unittest.cc",
   ]
   deps = [
     ":common",
     "//base",
     "//testing/gtest",
   ]
 }