Convert some component source sets to static library

components/subresource_filter/content/common/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.
 
-source_set("common") {
+static_library("common") {
   sources = [
     "subresource_filter_message_generator.cc",
     "subresource_filter_message_generator.h",
     "subresource_filter_messages.h",
   ]
   deps = [
     "//components/subresource_filter/core/common",
     "//content/public/common",
     "//ipc",
   ]
 }