Add missing files to rtc_base.

Bug: webrtc:7640
Change-Id: Ia9b7f0c1c10765e7064be8d2758c1c2e68e667ed
Reviewed-on: https://webrtc-review.googlesource.com/34649
Commit-Queue: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21355}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 41bd74e..7349f17 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -570,6 +570,7 @@
     "crc32.h",
     "cryptstring.cc",
     "cryptstring.h",
+    "dscp.h",
     "filerotatingstream.cc",
     "filerotatingstream.h",
     "fileutils.cc",
@@ -582,6 +583,7 @@
     "httpcommon.h",
     "ipaddress.cc",
     "ipaddress.h",
+    "keep_ref_until_done.h",
     "messagedigest.cc",
     "messagedigest.h",
     "messagehandler.cc",
@@ -597,6 +599,7 @@
     "network_constants.h",
     "networkmonitor.cc",
     "networkmonitor.h",
+    "networkroute.h",
     "nullsocketserver.cc",
     "nullsocketserver.h",
     "openssl.h",