Convert some component source sets to static library

components/constrained_window/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.
 
-source_set("constrained_window") {
+static_library("constrained_window") {
   sources = [
     "constrained_window_views.cc",
     "constrained_window_views.h",
     "constrained_window_views_client.h",
   ]
 
   deps = [
     "//components/guest_view/browser",
     "//components/web_modal",
     "//skia",
     "//ui/views",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "constrained_window_views_unittest.cc",
   ]
 
   deps = [
     ":constrained_window",
     "//components/web_modal:test_support",
     "//ui/views:test_support",
   ]
 }