Add user_prefs and visitedlink components to GN build.

components/visitedlink/browser/BUILD.gn

Index: components/visitedlink/browser/BUILD.gn
diff --git a/components/visitedlink/browser/BUILD.gn b/components/visitedlink/browser/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..4fce197308a3efe8cc7a70b1aeda032bdf220f61
--- /dev/null
+++ b/components/visitedlink/browser/BUILD.gn
@@ -0,0 +1,21 @@
+# 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("browser") {
+  output_name = "visitedlink_browser"
+  sources = [
+    "visitedlink_delegate.h",
+    "visitedlink_event_listener.cc",
+    "visitedlink_event_listener.h",
+    "visitedlink_master.cc",
+    "visitedlink_master.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/visitedlink/common",
+    "//content/public/browser",
+    "//content/public/common",
+  ]
+}