Make rawrtc build

Change-Id: I077e43c6aaee27307dadb97a7352c8412b735519
diff --git a/third_party/rawrtc/rawrtc-data-channel/WORKSPACE b/third_party/rawrtc/rawrtc-data-channel/WORKSPACE
new file mode 100644
index 0000000..957c8b1
--- /dev/null
+++ b/third_party/rawrtc/rawrtc-data-channel/WORKSPACE
@@ -0,0 +1 @@
+workspace(name = "com_github_rawrtc_rawrtc_data_channel")