Fix gn installer/linux/BUILD.gn with target_arch=arm

chrome/installer/linux/BUILD.gn

 # Copyright 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("//build/config/chrome_build.gni")
 import("//build/config/features.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/util/process_version.gni")
 import("//build/util/version.gni")
 import("//chrome/process_version_rc_template.gni")  # For branding_file_path.
@@ skipping 220 matching lines @@
   ]
 
   if (current_cpu == "x86") {
     packaging_files_binaries += [ "$root_out_dir/nacl_irt_x86_32.nexe" ]
   } else if (current_cpu == "x64") {
     packaging_files_binaries += [ "$root_out_dir/nacl_irt_x86_64.nexe" ]
   } else if (current_cpu == "arm") {
     packaging_files_binaries += [ "$root_out_dir/nacl_irt_arm.nexe" ]
   }
 
-  if (is_chrome_branded) {
+  # The widevine BUILD.gn only produces shared libraries for x86 and x64
+  if (is_chrome_branded && (current_cpu == "x86" || current_cpu == "x64")) {
     packaging_files_binaries += [
       "$root_out_dir/$widevine_cdm_path/libwidevinecdmadapter.so",
       "$root_out_dir/$widevine_cdm_path/libwidevinecdm.so",
     ]
   }
 
   if (is_asan) {
     packaging_files_binaries += [ "$root_out_dir/lib/libc++.so" ]
   }
 
@@ skipping 101 matching lines @@
 # Other packages that we support that aren't included in the default "linux"
 # target.
 linux_package("trunk") {
   channel = "trunk"
 }
 if (is_asan) {
   linux_package("asan") {
     channel = "asan"
   }
 }