Convert some component source sets to static library

components/ntp_snippets/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.
 
 import("//build/config/ui.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
 }
 
 # GYP version: components/ntp_snippets.gypi:ntp_snippets
-source_set("ntp_snippets") {
+static_library("ntp_snippets") {
   sources = [
     "content_suggestion.cc",
     "content_suggestion.h",
     "content_suggestions_category.h",
     "content_suggestions_category_status.cc",
     "content_suggestions_category_status.h",
     "content_suggestions_provider.cc",
     "content_suggestions_provider.h",
     "content_suggestions_service.cc",
     "content_suggestions_service.h",
@@ skipping 73 matching lines @@
     "//components/leveldb_proto:test_support",
     "//components/signin/core/browser:test_support",
     "//components/signin/core/common",
     "//components/sync_driver:test_support",
     "//components/variations",
     "//net:test_support",
     "//testing/gtest",
     "//third_party/icu/",
   ]
 }