chromium: Enable swiftshader by default.

This makes it possible to use chromium headless with WebGL
(e.g. for webdriver tests) without having to rebuild from source.

The upstram default is to enable, thus simply removing our disabling switch.

Also fixes #41918.

pkgs/applications/networking/browsers/chromium/browser.nix

@@ -18,6 +18,16 @@ mkChromiumDerivation (base: rec {
     cp -vLR "$buildPath/locales" "$buildPath/resources" "$libExecPath/"
     cp -v "$buildPath/chrome" "$libExecPath/$packageName"
 
+    # Swiftshader
+    # See https://stackoverflow.com/a/4264351/263061 for the find invocation.
+    if [ -n "$(find "$buildPath/swiftshader/" -maxdepth 1 -name '*.so' -print -quit)" ]; then
+      echo "Swiftshader files found; installing"
+      mkdir -p "$libExecPath/swiftshader"
+      cp -v "$buildPath/swiftshader/"*.so "$libExecPath/swiftshader/"
+    else
+      echo "Swiftshader files not found"
+    fi
+
     mkdir -p "$sandbox/bin"
     cp -v "$buildPath/chrome_sandbox" "$sandbox/bin/${sandboxExecutableName}"
 

pkgs/applications/networking/browsers/chromium/common.nix

@@ -244,7 +244,6 @@ let
       is_clang = stdenv.cc.isClang;
       clang_use_chrome_plugins = false;
       blink_symbol_level = 0;
-      enable_swiftshader = false;
       fieldtrial_testing_like_official_build = true;
 
       # Google API keys, see: