Add an experimental Carosuel RenderableUnit.

PiperOrigin-RevId: 245474448
Change-Id: Iba4a5f1b2478a0996d7df30c3a6c3006ffd2aac8
diff --git a/src/main/proto/search/now/wire/feed/feature.proto b/src/main/proto/search/now/wire/feed/feature.proto
index 08cb850..f99f28d 100644
--- a/src/main/proto/search/now/wire/feed/feature.proto
+++ b/src/main/proto/search/now/wire/feed/feature.proto
@@ -14,12 +14,12 @@
 
 syntax = "proto2";
 
-import "src/main/proto/search/now/wire/feed/content_id.proto";
-
 package search.now.wire.feed;
 
 option optimize_for=LITE_RUNTIME;
 
+import "src/main/proto/search/now/wire/feed/content_id.proto";
+
 option java_package = "com.google.search.now.wire.feed";
 option java_outer_classname = "FeatureProto";
 
@@ -37,6 +37,8 @@
     CONTENT = 3;
     CLUSTER = 4;
     TOKEN = 5;
+    // Note: This is an experimental feature.
+    CAROUSEL = 6;
   }
   optional RenderableUnit renderable_unit = 2;