[results feed] Show only commits with changed results, by default

Change-Id: I2b17c22bc54bf158fe9f3adc2b2c7bd4e36d9575
Reviewed-on: https://dart-review.googlesource.com/c/dart_ci/+/128860
Reviewed-by: Alexander Thomas <athom@google.com>
diff --git a/results_feed/lib/src/model/comment.dart b/results_feed/lib/src/model/comment.dart
index aeafdf5..40434b5 100644
--- a/results_feed/lib/src/model/comment.dart
+++ b/results_feed/lib/src/model/comment.dart
@@ -54,7 +54,8 @@
         review = document.get('review'),
         patchset = document.get('patchset');
 
-  String approvedText() => approved ? 'approved' : '';
+  String approvedText() =>
+      (approved == null) ? "" : approved ? "approved" : "disapproved";
 
   int compareTo(Object other) => created.compareTo((other as Comment).created);
 }
diff --git a/results_feed/lib/src/services/filter_service.dart b/results_feed/lib/src/services/filter_service.dart
index d0d0f51..fa3de05 100644
--- a/results_feed/lib/src/services/filter_service.dart
+++ b/results_feed/lib/src/services/filter_service.dart
@@ -67,7 +67,7 @@
     return result;
   }
 
-  static const defaultShowAllCommits = true;
+  static const defaultShowAllCommits = false;
   static const defaultShowLatestFailures = false;
   static const defaultShowUnapprovedOnly = false;
   static const allConfigurationGroups = <String>[