Edit Screen: Load non-edit links as part of group1

If the links fail to load, combine the error into the group1 error
handling instead of displaying a separate error dialog.

Change-Id: I364c0249ec159c5f0277debfa4b23c0153631cae
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/editor/EditScreen.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/editor/EditScreen.java
index 47afb0a..fe4c395 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/editor/EditScreen.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/editor/EditScreen.java
@@ -178,12 +178,16 @@
       DiffApi.diff(revision, path)
         .base(base)
         .webLinksOnly()
-        .get(new GerritCallback<DiffInfo>() {
+        .get(group1.add(new AsyncCallback<DiffInfo>() {
           @Override
           public void onSuccess(DiffInfo diffInfo) {
             patchSetDiffInfo = diffInfo;
           }
-      });
+
+          @Override
+          public void onFailure(Throwable e) {
+          }
+      }));
     }
 
     ChangeEditApi.get(revision, path,