chromium: softlink system nodejs into third_party

somehow, the build seems to have changed with chromium 58, to not auto
download the node binary. It is needed to generate webui files and we
can substitute our own.

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

@@ -1,4 +1,4 @@
-{ stdenv, ninja, which
+{ stdenv, ninja, which, nodejs
 
 # default dependencies
 , bzip2, flac, speex, libopus
@@ -87,7 +87,7 @@ let
 
     nativeBuildInputs = [
       ninja which python2Packages.python perl pkgconfig
-      python2Packages.ply python2Packages.jinja2
+      python2Packages.ply python2Packages.jinja2 nodejs
     ];
 
     buildInputs = defaultDependencies ++ [
@@ -131,6 +131,9 @@ let
       }' gpu/config/gpu_control_list.cc
 
       patchShebangs .
+      # use our own nodejs
+      mkdir -p third_party/node/linux/node-linux-x64/bin
+      ln -s $(which node) third_party/node/linux/node-linux-x64/bin/node
     '' + optionalString (versionAtLeast version "52.0.0.0") ''
       sed -i -re 's/([^:])\<(isnan *\()/\1std::\2/g' \
         third_party/pdfium/xfa/fxbarcode/utils.h