Add built-in root certificates to dart:io SecureSocket.

runtime/tools/gyp/nss_configurations.gypi

Index: runtime/tools/gyp/nss_configurations.gypi
diff --git a/runtime/tools/gyp/nss_configurations.gypi b/runtime/tools/gyp/nss_configurations.gypi
index 74c857cb2ce16bf7b0b6a3e15f1a289c2395685d..ac3e6120000b9f7f9cd069167a6fa71e574e936e 100644
--- a/runtime/tools/gyp/nss_configurations.gypi
+++ b/runtime/tools/gyp/nss_configurations.gypi
@@ -10,9 +10,8 @@
 {
   'variables': {
     # Used by third_party/nss, which is from Chromium.
-    # When the NSS and related libraries gyp files are processed in
-    # Dartium, do not override the settings from Dartium.  The targets will
-    # not be built.
+    # Include the built-in set of root certificate authorities.
+    'exclude_nss_root_certs': 0,
     'os_posix%': 1,
     'os_bsd%': 0,
     'chromeos%': 0,