Remove the Widevine signature files from the Linux and ChromeOS builds

third_party/widevine/cdm/BUILD.gn

Index: third_party/widevine/cdm/BUILD.gn
diff --git a/third_party/widevine/cdm/BUILD.gn b/third_party/widevine/cdm/BUILD.gn
index 5c0268236621cda077b0eef656e72d2e74afb636..dda97991ca4b0c533ae7a5830d9e9d9195a86811 100644
--- a/third_party/widevine/cdm/BUILD.gn
+++ b/third_party/widevine/cdm/BUILD.gn
@@ -25,16 +25,10 @@ if (is_android) {
   if (is_chromeos) {
     widevine_cdm_version_h_file =
         "chromeos/$widevine_arch/widevine_cdm_version.h"
-    widevine_cdm_binary_files = [
-      "chromeos/$widevine_arch/libwidevinecdm.so",
-      "chromeos/$widevine_arch/libwidevinecdm.so.sig",
-    ]
+    widevine_cdm_binary_files = [ "chromeos/$widevine_arch/libwidevinecdm.so" ]
   } else if (is_linux) {
     widevine_cdm_version_h_file = "linux/$widevine_arch/widevine_cdm_version.h"
-    widevine_cdm_binary_files = [
-      "linux/$widevine_arch/libwidevinecdm.so",
-      "linux/$widevine_arch/libwidevinecdm.so.sig",
-    ]
+    widevine_cdm_binary_files = [ "linux/$widevine_arch/libwidevinecdm.so" ]
   } else if (is_win) {
     widevine_cdm_version_h_file = "win/$widevine_arch/widevine_cdm_version.h"
     widevine_cdm_binary_files = [