Use gerrit-theme.js by default when enableDefault set to true

Change-Id: I5c4e121da7c76c40b1089d70352f3aa12e28b1c6
diff --git a/Documentation/rest-api-config.txt b/Documentation/rest-api-config.txt
index f76e0b8..4473a8d 100644
--- a/Documentation/rest-api-config.txt
+++ b/Documentation/rest-api-config.txt
@@ -2011,7 +2011,7 @@
 UserConfigInfo] entity.
 |`default_theme`           |optional|
 URL to a default PolyGerrit UI theme plugin, if available.
-Located in `/static/gerrit-theme.html` by default.
+Located in `/static/gerrit-theme.js` by default.
 |=======================================
 
 [[sshd-info]]
diff --git a/java/com/google/gerrit/server/restapi/config/GetServerInfo.java b/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
index 1f4b468..beb7dfd 100644
--- a/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
+++ b/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
@@ -348,7 +348,7 @@
       // Return non-null theme path without checking for file existence. Even if the file doesn't
       // exist under the site path, it may be served from a CDN (in which case it's up to the admin
       // to also pass a proper asset path to the index Soy template).
-      return DEFAULT_THEME;
+      return DEFAULT_THEME_JS;
     }
     return null;
   }