Convert some component source sets to static library

components/drive/BUILD.gn

 # Copyright (c) 2015 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("//third_party/protobuf/proto_library.gni")
 
 static_library("drive") {
   sources = [
     "drive_api_util.cc",
     "drive_api_util.h",
@@ skipping 50 matching lines @@
     "//net:net",
     "//third_party/cacheinvalidation",
     "//third_party/leveldatabase",
     "//third_party/re2",
   ]
   public_deps = [
     ":proto",
   ]
 }
 
-source_set("drive_chromeos") {
+static_library("drive_chromeos") {
   sources = [
     "chromeos/change_list_loader.cc",
     "chromeos/change_list_loader.h",
     "chromeos/change_list_loader_observer.h",
     "chromeos/change_list_processor.cc",
     "chromeos/change_list_processor.h",
     "chromeos/directory_loader.cc",
     "chromeos/directory_loader.h",
     "chromeos/file_cache.cc",
     "chromeos/file_cache.h",
@@ skipping 100 matching lines @@
       ":drive",
       ":drive_chromeos",
       ":proto",
       "//base",
       "//components/prefs:test_support",
       "//content/test:test_support",
       "//google_apis:test_support",
     ]
   }
 }