Rename source_prereqs to inputs in the GN build.

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.
 
 source_ids = "//third_party/usb_ids/usb.ids"
 generated_ids = "$target_gen_dir/usb_ids_gen.cc"
 
 source_set("usb") {
   sources = [
     "usb_ids.cc",
     "usb_ids.h",
     generated_ids,
   ]
   deps = [
     ":usb_device_ids",
     "//base",
   ]
 }
 
 action("usb_device_ids") {
   script = "//device/usb/tools/usb_ids.py"
-  source_prereqs = [ source_ids ]
+  inputs = [ source_ids ]
   outputs = [ generated_ids ]
   args = [
     "-i", rebase_path(source_ids,  root_build_dir),
     "-o", rebase_path(generated_ids, root_build_dir),
   ]
 
   # Only the device_usb target can depend on us.
   visibility = [ ":usb" ]
 }