Control TaskScheduler initialization params in renderers via field trial.

components/task_scheduler_util/renderer/BUILD.gn

Index: components/task_scheduler_util/renderer/BUILD.gn
diff --git a/components/task_scheduler_util/renderer/BUILD.gn b/components/task_scheduler_util/renderer/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..e5964d6a10b6eb6137150e52b146e2cfd8be8e6c
--- /dev/null
+++ b/components/task_scheduler_util/renderer/BUILD.gn
@@ -0,0 +1,15 @@
+# Copyright 2017 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 = [
+    "initialization.cc",
+    "initialization.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/task_scheduler_util/common",
+  ]
+}