chromium: Add support for pulseaudio.

Which is enabled by default if neither pulseaudio or chromium.pulseaudio is
explicitly set. The reason is that chromium falls back to ALSA in case no
pulseaudio is available.

In addition it was necessary to patch media.gyp to ignore the array-out-of-
bounds warning.

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

@@ -18,6 +18,7 @@
 , gconf # config.gnome
 , libgcrypt # config.gnome || config.cups
 , nss, openssl # config.openssl
+, pulseaudio # config.pulseaudio
 , libselinux # config.selinux
 }:
 
@@ -32,6 +33,7 @@ let
     gnomeKeyring = false;
     proprietaryCodecs = true;
     cups = false;
+    pulseaudio = getConfig ["pulseaudio"] true;
   };
 
   sourceInfo = import ./source.nix;
@@ -98,14 +100,16 @@ in stdenv.mkDerivation rec {
   ] ++ stdenv.lib.optional config.gnomeKeyring libgnome_keyring
     ++ stdenv.lib.optionals config.gnome [ gconf libgcrypt ]
     ++ stdenv.lib.optional config.selinux libselinux
-    ++ stdenv.lib.optional config.cups libgcrypt;
+    ++ stdenv.lib.optional config.cups libgcrypt
+    ++ stdenv.lib.optional config.pulseaudio pulseaudio;
 
   opensslPatches = stdenv.lib.optional config.openssl openssl.patches;
 
   prePatch = "patchShebangs .";
 
   patches = stdenv.lib.optional (!config.selinux) ./enable_seccomp.patch
-         ++ stdenv.lib.optional config.cups ./cups_allow_deprecated.patch;
+         ++ stdenv.lib.optional config.cups ./cups_allow_deprecated.patch
+         ++ stdenv.lib.optional config.pulseaudio ./pulseaudio_array_bounds.patch;
 
   postPatch = stdenv.lib.optionalString config.openssl ''
     cat $opensslPatches | patch -p1 -d third_party/openssl/openssl
@@ -118,6 +122,7 @@ in stdenv.mkDerivation rec {
     use_gnome_keyring = config.gnomeKeyring;
     use_gconf = config.gnome;
     use_gio = config.gnome;
+    use_pulseaudio = config.pulseaudio;
     disable_nacl = !config.nacl;
     use_openssl = config.openssl;
     selinux = config.selinux;

pkgs/applications/networking/browsers/chromium/pulseaudio_array_bounds.patch

@@ -0,0 +1,12 @@
+diff --git a/media/media.gyp b/media/media.gyp
+index 2a8c6c6..66ca767 100644
+--- a/media/media.gyp
++++ b/media/media.gyp
+@@ -399,6 +399,7 @@
+             ['use_pulseaudio == 1', {
+               'cflags': [
+                 '<!@(pkg-config --cflags libpulse)',
++                '-Wno-array-bounds',
+               ],
+               'link_settings': {
+                 'libraries': [