Add gyp files to build NSS in Dart

runtime/bin/bin.gypi

Index: runtime/bin/bin.gypi
diff --git a/runtime/bin/bin.gypi b/runtime/bin/bin.gypi
index c851c9757a7383021ec6bb7fdd95b1b5c3cc3edc..1385c130f85fee5fb6faa0a3986379b7adf71128 100644
--- a/runtime/bin/bin.gypi
+++ b/runtime/bin/bin.gypi
@@ -260,6 +260,7 @@
         'generate_json_cc_file',
         'generate_uri_cc_file',
         'generate_utf_cc_file',
+        'nss',
       ],
       'include_dirs': [
         '..',
@@ -303,6 +304,28 @@
       ],
     },
     {
+      'target_name': 'nss',
+      'type': 'none',
+      'dependencies': [
+        'bin/net/nss.gyp:nss',
+        'bin/net/nss.gyp:nspr',
+        'bin/net/nss.gyp:nssckbi',
+        'bin/net/nss.gyp:nss_static',
+        'bin/net/ssl.gyp:libssl',
+        'bin/net/zlib.gyp:zlib',
+        'bin/net/sqlite.gyp:sqlite',
+      ],
+      'export_dependent_settings': [

[Ivan Posva, 2012/11/02 15:58:52]

Can you briefly explain what this does and why it was needed?

[Bill Hesse, 2012/11/02 16:08:15]

The targets like nss and zlib include direct-dependent settings for include
directories and defines, and to pass these up to the libdart_builtin, that is
actually compiling against the libraries and the header files, we need to pass
them through this intermediate target.  That is what export_dependent_settings
does.

We could avoid this by just putting the targets as dependencies in
libdart_builtin, and removing this target.  Do you think we should do this?

+        'bin/net/nss.gyp:nss',
+        'bin/net/nss.gyp:nspr',
+        'bin/net/nss.gyp:nssckbi',
+        'bin/net/nss.gyp:nss_static',
+        'bin/net/ssl.gyp:libssl',
+        'bin/net/zlib.gyp:zlib',
+        'bin/net/sqlite.gyp:sqlite',
+      ],
+    },
+    {
       'target_name': 'libdart_withcore',
       'type': 'static_library',
       'dependencies': [