Adding a new component, Previews.

components/previews/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("link_header_util") {
+static_library("previews") {
   sources = [
-    "link_header_util.cc",
-    "link_header_util.h",
+    "previews_experiments.cc",
+    "previews_experiments.h",
   ]
 
   deps = [
     "//base",
-    "//net",
+    "//components/variations",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
-    "link_header_util_unittest.cc",
+    "previews_experiments_unittest.cc",
   ]
 
   deps = [
-    ":link_header_util",
+    ":previews",
     "//base",
-    "//net",
+    "//components/variations",
     "//testing/gtest",
   ]
 }