Add AddNetwork message to pairing API.

BUG=None

Review URL: https://codereview.chromium.org/1090483002

Cr-Commit-Position: refs/heads/master@{#326206}
diff --git a/components/pairing/pairing_api.proto b/components/pairing/pairing_api.proto
index 0d8e6680..856feae6 100644
--- a/components/pairing/pairing_api.proto
+++ b/components/pairing/pairing_api.proto
@@ -86,3 +86,12 @@
   optional int32 api_version = 1;
   optional ErrorParameters parameters = 2;
 }
+
+message AddNetworkParameters {
+  optional string onc_spec = 1;
+}
+
+message AddNetwork {
+  optional int32 api_version = 1;
+  optional AddNetworkParameters parameters = 2;
+}