nixos/browserpass: update for v3

See https://github.com/browserpass/browserpass-native/issues/31

Additionally browserpass was removed from systemPackages, because it
doesn't need to be installed, browsers will get the path to the binary
from the native messaging host JSON.

nixos/modules/programs/browserpass.nix

@@ -4,15 +4,34 @@ with lib;
 
 {
 
-  ###### interface
+  options.programs.browserpass.enable = mkEnableOption "Browserpass native messaging host";
-  options = {
-    programs.browserpass.enable = mkEnableOption "the NativeMessaging configuration for Chromium, Chrome, and Vivaldi.";
-  };
 
-  ###### implementation
   config = mkIf config.programs.browserpass.enable {
-    environment.systemPackages = [ pkgs.browserpass ];
+    environment.etc = let
-    environment.etc = {
+      appId = "com.github.browserpass.native.json";
+      source = part: "${pkgs.browserpass}/lib/browserpass/${part}/${appId}";
+    in {
+      # chromium
+      "chromium/native-messaging-hosts/${appId}".source = source "hosts/chromium";
+      "chromium/policies/managed/${appId}".source = source "policies/chromium";
+
+      # chrome
+      "opt/chrome/native-messaging-hosts/${appId}".source = source "hosts/chromium";
+      "opt/chrome/policies/managed/${appId}".source = source "policies/chromium";
+
+      # vivaldi
+      "opt/vivaldi/native-messaging-hosts/${appId}".source = source "hosts/chromium";
+      "opt/vivaldi/policies/managed/${appId}".source = source "policies/chromium";
+
+      # brave
+      "opt/brave/native-messaging-hosts/${appId}".source = source "hosts/chromium";
+      "opt/brave/policies/managed/${appId}".source = source "policies/chromium";
+    }
+    # As with the v2 backwards compatibility in the pkgs.browserpass
+    # declaration, this part can be removed once the browser extension
+    # auto-updates to v3 (planned 2019-04-13, see
+    # https://github.com/browserpass/browserpass-native/issues/31)
+    // {
       "chromium/native-messaging-hosts/com.dannyvankooten.browserpass.json".source = "${pkgs.browserpass}/etc/chrome-host.json";
       "chromium/policies/managed/com.dannyvankooten.browserpass.json".source = "${pkgs.browserpass}/etc/chrome-policy.json";
       "opt/chrome/native-messaging-hosts/com.dannyvankooten.browserpass.json".source = "${pkgs.browserpass}/etc/chrome-host.json";