Rework to avoid a full rebuild for widevine.

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

@@ -1,47 +1,8 @@
-{ stdenv, mkChromiumDerivation, channel, upstream-info, gcc, glib, nspr, nss, patchelfUnstable, enableWideVine }:
+{ stdenv, mkChromiumDerivation, channel }:
 
 with stdenv.lib;
 
-let
+mkChromiumDerivation (base: rec {
-  mkrpath = p: "${makeSearchPathOutput "lib" "lib64" p}:${makeLibraryPath p}";
-  widevine = stdenv.mkDerivation {
-    name = "chromium-binary-plugin-widevine";
-
-    src = upstream-info.binary;
-
-    nativeBuildInputs = [ patchelfUnstable ];
-
-    phases = [ "unpackPhase" "patchPhase" "installPhase" "checkPhase" ];
-
-    unpackCmd = let
-      chan = if upstream-info.channel == "dev"    then "chrome-unstable"
-        else if upstream-info.channel == "stable" then "chrome"
-        else "chrome-${upstream-info.channel}";
-    in ''
-      mkdir -p plugins
-      ar p "$src" data.tar.xz | tar xJ -C plugins --strip-components=4 \
-        ./opt/google/${chan}/libwidevinecdm.so
-    '';
-
-    doCheck = true;
-    checkPhase = ''
-      ! find -iname '*.so' -exec ldd {} + | grep 'not found'
-    '';
-
-    PATCH_RPATH = mkrpath [ gcc.cc glib nspr nss ];
-
-    patchPhase = ''
-      patchelf --set-rpath "$PATCH_RPATH" libwidevinecdm.so
-    '';
-
-    installPhase = ''
-      install -vD libwidevinecdm.so \
-        "$out/lib/libwidevinecdm.so"
-    '';
-
-    meta.platforms = platforms.x86_64;
-  };
-in mkChromiumDerivation (base: rec {
   name = "chromium-browser";
   packageName = "chromium";
   buildTargets = [ "mksnapshot" "chrome_sandbox" "chrome" ];
@@ -91,8 +52,6 @@ in mkChromiumDerivation (base: rec {
       -e '/\[Desktop Entry\]/a\' \
       -e 'StartupWMClass=chromium-browser' \
       $out/share/applications/chromium-browser.desktop
-
-    ${optionalString enableWideVine "ln -s ${widevine}/lib/libwidevinecdm.so \"$libExecPath/libwidevinecdm.so\""}
   '';
 
   passthru = { inherit sandboxExecutableName; };

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

@@ -24,7 +24,6 @@
 
 # package customization
 , enableNaCl ? false
-, enableWideVine ? false
 , useVaapi ? false
 , gnomeSupport ? false, gnome ? null
 , gnomeKeyringSupport ? false, libgnome-keyring3 ? null
@@ -133,11 +132,12 @@ let
       ++ optional pulseSupport libpulseaudio
       ++ optional (versionAtLeast version "72") jdk.jre;
 
-    patches = optional enableWideVine ./patches/widevine.patch ++ [
+    patches = [
       ./patches/nix_plugin_paths_68.patch
       ./patches/remove-webp-include-69.patch
       ./patches/jumbo-sorted.patch
       ./patches/no-build-timestamps.patch
+      ./patches/widevine.patch
 
       # Unfortunately, chromium regularly breaks on major updates and
       # then needs various patches backported in order to be compiled with GCC.
@@ -245,7 +245,7 @@ let
       use_gnome_keyring = gnomeKeyringSupport;
       use_gio = gnomeSupport;
       enable_nacl = enableNaCl;
-      enable_widevine = enableWideVine;
+      enable_widevine = true;
       use_cups = cupsSupport;
 
       treat_warnings_as_errors = false;

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

@@ -2,6 +2,8 @@
 , makeWrapper, ed
 , glib, gtk3, gnome3, gsettings-desktop-schemas
 , libva ? null
+, gcc, nspr, nss, patchelfUnstable, runCommand
+, lib
 
 # package customization
 , channel ? "stable"
@@ -34,23 +36,71 @@ in let
     mkChromiumDerivation = callPackage ./common.nix {
       inherit enableNaCl gnomeSupport gnome
               gnomeKeyringSupport proprietaryCodecs cupsSupport pulseSupport
-              useVaapi
+              useVaapi;
-              enableWideVine;
     };
 
-    browser = callPackage ./browser.nix { inherit channel enableWideVine; };
+    browser = callPackage ./browser.nix { inherit channel; };
 
     plugins = callPackage ./plugins.nix {
       inherit enablePepperFlash;
     };
   };
 
+  mkrpath = p: "${lib.makeSearchPathOutput "lib" "lib64" p}:${lib.makeLibraryPath p}";
+  widevine = let upstream-info = chromium.upstream-info; in stdenv.mkDerivation {
+    name = "chromium-binary-plugin-widevine";
+
+    src = upstream-info.binary;
+
+    nativeBuildInputs = [ patchelfUnstable ];
+
+    phases = [ "unpackPhase" "patchPhase" "installPhase" "checkPhase" ];
+
+    unpackCmd = let
+      chan = if upstream-info.channel == "dev"    then "chrome-unstable"
+        else if upstream-info.channel == "stable" then "chrome"
+        else "chrome-${upstream-info.channel}";
+    in ''
+      mkdir -p plugins
+      ar p "$src" data.tar.xz | tar xJ -C plugins --strip-components=4 \
+        ./opt/google/${chan}/libwidevinecdm.so
+    '';
+
+    doCheck = true;
+    checkPhase = ''
+      ! find -iname '*.so' -exec ldd {} + | grep 'not found'
+    '';
+
+    PATCH_RPATH = mkrpath [ gcc.cc glib nspr nss ];
+
+    patchPhase = ''
+      patchelf --set-rpath "$PATCH_RPATH" libwidevinecdm.so
+    '';
+
+    installPhase = ''
+      install -vD libwidevinecdm.so \
+        "$out/lib/libwidevinecdm.so"
+    '';
+
+    meta.platforms = lib.platforms.x86_64;
+  };
+
   suffix = if channel != "stable" then "-" + channel else "";
 
   sandboxExecutableName = chromium.browser.passthru.sandboxExecutableName;
 
   version = chromium.browser.version;
 
+  chromiumWV = let browser = chromium.browser; in if enableWideVine then
+    runCommand (browser.name + "-wv") { version = browser.version; }
+      ''
+        mkdir -p $out
+        cp -R ${browser}/* $out/
+        chmod u+w $out/libexec/chromium*
+        cp ${widevine}/lib/libwidevinecdm.so $out/libexec/chromium/
+        # patchelf?
+      ''
+    else browser;
 in stdenv.mkDerivation {
   name = "chromium${suffix}-${version}";
   inherit version;
@@ -68,7 +118,7 @@ in stdenv.mkDerivation {
   outputs = ["out" "sandbox"];
 
   buildCommand = let
-    browserBinary = "${chromium.browser}/libexec/chromium/chromium";
+    browserBinary = "${chromiumWV}/libexec/chromium/chromium";
     getWrapperFlags = plugin: "$(< \"${plugin}/nix-support/wrapper-flags\")";
     libPath = stdenv.lib.makeLibraryPath ([]
       ++ stdenv.lib.optional useVaapi libva