Fix issue 6834.

Repost of Reitveld issue 1563803.
Patch by: Daniel Kurka

Review at http://gwt-code-reviews.appspot.com/1609804

Review by: rice@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10858 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/src/com/google/gwt/geolocation/client/Geolocation.java b/user/src/com/google/gwt/geolocation/client/Geolocation.java
index 81f11f5..16ac210 100644
--- a/user/src/com/google/gwt/geolocation/client/Geolocation.java
+++ b/user/src/com/google/gwt/geolocation/client/Geolocation.java
@@ -294,8 +294,10 @@
       (callback, err.code, err.message);
     });
 
+    var id = -1;
     if (@com.google.gwt.geolocation.client.Geolocation::isSupported()) {
-      $wnd.navigator.geolocation.watchPosition(success, failure, opt);
+      id = $wnd.navigator.geolocation.watchPosition(success, failure, opt);
     }
+    return id;
   }-*/;
 }