media: More cleanup in cdm_paths.*

media/cdm/ppapi/cdm_paths.gni

 # 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.
 
 # This file defines output paths for the CDM adapters and CDMs.
 
 # Naming and folder structure below are following the recommendation for Chrome
 # components. Component-updated CDMs must follow the same recommendation.
 
 # Note: This file must be in sync with cdm_paths.cc
 
 # OS name for components is close to "target_os" but has some differences.
 # Explicitly define what we use to avoid confusion.
 if (is_chromeos) {
   component_os = "cros"
 } else if (is_linux) {
   component_os = "linux"
 } else if (is_win) {
   component_os = "win"
 } else if (is_mac) {
   component_os = "mac"
 } else {
-  component_os = "$target_os"
+  component_os = "unsupported_platform"
+}
+
+if (target_cpu == "x86" || target_cpu == "x64" || target_cpu == "arm") {
+  component_arch = "$target_cpu"
+} else {
+  component_arch = "unsupported_arch"
 }
 
 # Only enable platform specific path for Win and Mac, where CDMs are Chrome
 # components.
 # TODO(xhwang): Improve how we enable platform specific path. See
 # http://crbug.com/468584
-if (is_win || is_mac) {
-  # Architecture name for components is the same as "<(target_cpu)".
+if ((is_win || is_mac) && (target_cpu == "x86" || target_cpu == "x64")) {
   _platform_specific_path =
-      "_platform_specific/$component_os" + "_" + "$target_cpu"
+      "_platform_specific/$component_os" + "_" + "$component_arch"
 
   # Path of Clear Key and Widevine CDMs relative to the output dir.
   clearkey_cdm_path = "ClearKeyCdm/$_platform_specific_path"
   widevine_cdm_path = "WidevineCdm/$_platform_specific_path"
 } else {
   clearkey_cdm_path = "."
   widevine_cdm_path = "."
 }