chromium: install plasma browser integration

Reuse existing plasmaSupport option to install browser integration
package.

modules/programs/chromium.nix

@@ -80,7 +80,19 @@ let
         type = types.bool;
         default = false;
         example = true;
-        description = "Whether to enable the 'Use QT' theme for ${name}.";
+        description = "Whether to enable the 'Use QT' theme for ${name} on Linux.";
+      };
+
+      plasmaBrowserIntegrationPackage = mkOption {
+        inherit visible;
+        type = types.package;
+        default = pkgs.kdePackages.plasma-browser-integration;
+        defaultText = literalExpression "pkgs.kdePackages.plasma-browser-integration";
+        example = literalExpression "pkgs.kdePackages.plasma-browser-integration";
+        description = ''
+          Package to use for the Plasma browser integration native messaging
+          host on Linux.
+        '';
       };
     }
     // {
@@ -103,7 +115,7 @@ let
         default = [ ];
         example = literalExpression ''
           [
-            pkgs.kdePackages.plasma-browser-integration
+            pkgs.keepassxc
           ]
         '';
         description = ''
@@ -257,9 +269,15 @@ let
         value.source = pkg;
       };
 
+      plasmaSupportEnabled = pkgs.stdenv.isLinux && (cfg.plasmaSupport or false);
+
+      nativeMessagingHosts = lib.unique (
+        cfg.nativeMessagingHosts ++ lib.optional plasmaSupportEnabled cfg.plasmaBrowserIntegrationPackage
+      );
+
       nativeMessagingHostsJoined = pkgs.symlinkJoin {
         name = "${effectiveBrowser}-native-messaging-hosts";
-        paths = cfg.nativeMessagingHosts;
+        paths = nativeMessagingHosts;
       };
 
     in
@@ -290,12 +308,12 @@ let
       programs.${browser}.finalPackage =
         if cfg.package == null then
           null
-        else if cfg.commandLineArgs != [ ] || (cfg.plasmaSupport or false) then
+        else if cfg.commandLineArgs != [ ] || plasmaSupportEnabled then
           cfg.package.override (
             lib.optionalAttrs (cfg.commandLineArgs != [ ]) {
               commandLineArgs = lib.concatStringsSep " " cfg.commandLineArgs;
             }
-            // lib.optionalAttrs (cfg.plasmaSupport or false) {
+            // lib.optionalAttrs plasmaSupportEnabled {
               plasmaSupport = true;
               inherit (pkgs) kdePackages;
             }
@@ -310,7 +328,7 @@ let
         lib.optionalAttrs supportsUserExtensions (lib.listToAttrs (map extensionJson cfg.extensions))
         // lib.listToAttrs (map dictionary cfg.dictionaries)
         // {
-          "${configDir}/NativeMessagingHosts" = lib.mkIf (cfg.nativeMessagingHosts != [ ]) {
+          "${configDir}/NativeMessagingHosts" = lib.mkIf (nativeMessagingHosts != [ ]) {
             source = "${nativeMessagingHostsJoined}/etc/chromium/native-messaging-hosts";
             recursive = true;
           };

tests/modules/programs/chromium/plasma-support-command-line-args.nix

@@ -1,4 +1,9 @@
-{ config, lib, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 let
   chromePackage =
     let
@@ -29,6 +34,20 @@ let
         };
     in
     mkPackage { name = "google-chrome"; };
+
+  plasmaBrowserIntegrationPackage = config.lib.test.mkStubPackage {
+    name = "plasma-browser-integration";
+    buildScript = ''
+      mkdir -p $out/etc/chromium/native-messaging-hosts
+      echo test > $out/etc/chromium/native-messaging-hosts/org.kde.plasma.browser_integration.json
+    '';
+  };
+
+  nativeHostsDir =
+    if pkgs.stdenv.hostPlatform.isDarwin then
+      "Library/Application Support/Google/Chrome/NativeMessagingHosts"
+    else
+      ".config/google-chrome/NativeMessagingHosts";
 in
 {
   programs.google-chrome = {
@@ -39,6 +58,7 @@ in
       "--ignore-gpu-blocklist"
     ];
     plasmaSupport = true;
+    inherit plasmaBrowserIntegrationPackage;
   };
 
   nmt.script = ''
@@ -53,7 +73,20 @@ in
       "${config.programs.google-chrome.finalPackage}/override-info" \
       ${builtins.toFile "google-chrome-override-info" ''
         commandLineArgs=--enable-logging=stderr --ignore-gpu-blocklist
-        plasmaSupport=true
+        plasmaSupport=${lib.boolToString pkgs.stdenv.hostPlatform.isLinux}
       ''}
+
+    ${
+      if pkgs.stdenv.hostPlatform.isLinux then
+        ''
+          assertFileExists \
+            "home-files/${nativeHostsDir}/org.kde.plasma.browser_integration.json"
+        ''
+      else
+        ''
+          assertPathNotExists \
+            "home-files/${nativeHostsDir}/org.kde.plasma.browser_integration.json"
+        ''
+    }
   '';
 }