Convert some GN test support targets to static libs.

device/usb/BUILD.gn

 # Copyright (c) 2013 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/features.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
 assert(!is_ios)
 
 if (is_android) {
   import("//build/config/android/rules.gni")  # For generate_jni().
 }
 
 source_ids = "//third_party/usb_ids/usb.ids"
 generated_ids = "$target_gen_dir/usb_ids_gen.cc"
 
-source_set("usb") {
+static_library("usb") {
   sources = [
     "android/usb_jni_registrar.cc",
     "android/usb_jni_registrar.h",
     "usb_configuration_android.cc",
     "usb_configuration_android.h",
     "usb_descriptors.cc",
     "usb_descriptors.h",
     "usb_device.cc",
     "usb_device.h",
     "usb_device_android.cc",
@@ skipping 67 matching lines @@
   }
 
   if (is_chromeos) {
     deps += [
       "//chromeos",
       "//dbus",
     ]
   }
 }
 
-source_set("test_support") {
+static_library("test_support") {
   testonly = true
 
   sources = [
     "fake_usb_device_handle.cc",
     "fake_usb_device_handle.h",
     "mock_usb_device.cc",
     "mock_usb_device.h",
     "mock_usb_device_handle.cc",
     "mock_usb_device_handle.h",
     "mock_usb_service.cc",
@@ skipping 87 matching lines @@
     jni_package = "device"
   }
 
   android_library("java") {
     java_files = java_sources_needing_jni
     deps = [
       "//base:base_java",
     ]
   }
 }