chromium: Revert zlib changes for v22 and higher.

SVN revision 151720 breaks the build with system zlib, see:

http://src.chromium.org/viewvc/chrome?view=rev&revision=151720

The issue here is, that r151720 introduces changes directly in zlib, which
aren't upstream and unfortunately there is no more information stating the exact
reasons for this change, as all references to it are not publicly available:

http://crbug.com/139744
https://chromiumcodereview.appspot.com/10837057

So for the moment, we're going to add a patch, which applies to v22 and higher,
which essentially reverts r151720, until either more information on the issue is
available or it is resolved upstream.

As someone has already reported the issue, we just need to track the following
issue:

http://crbug.com/143623

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

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

@@ -81,6 +81,18 @@ let
     pre22 = stdenv.lib.versionOlder sourceInfo.version "22.0.0.0";
   in if pre22 then ./enable_seccomp.patch else ./enable_seccomp22.patch;
 
+  # XXX: this reverts r151720 to prevent http://crbug.com/143623
+  maybeRevertZlibChanges = let
+    below22 = stdenv.lib.versionOlder sourceInfo.version "22.0.0.0";
+    patch = fetchurl {
+      name = "revert-r151720";
+      url = "http://git.chromium.org/gitweb/?p=chromium.git;a=commitdiff_plain;"
+          + "hp=4419ec6414b33b6b19bb2e380b4998ed5193ecab;"
+          + "h=0fabb4fda7059a8757422e8a44e70deeab28e698";
+      sha256 = "0n0d6mkg89g8q63cifapzpg9dxfs2n6xvk4k13szhymvf67b77pf";
+    };
+  in stdenv.lib.optional (!below22) patch;
+
 in stdenv.mkDerivation rec {
   name = "${packageName}-${version}";
   packageName = "chromium";
@@ -114,7 +126,8 @@ in stdenv.mkDerivation rec {
 
   patches = stdenv.lib.optional (!config.selinux) seccompPatch
          ++ stdenv.lib.optional config.cups ./cups_allow_deprecated.patch
-         ++ stdenv.lib.optional config.pulseaudio ./pulseaudio_array_bounds.patch;
+         ++ stdenv.lib.optional config.pulseaudio ./pulseaudio_array_bounds.patch
+         ++ maybeRevertZlibChanges;
 
   postPatch = stdenv.lib.optionalString config.openssl ''
     cat $opensslPatches | patch -p1 -d third_party/openssl/openssl