Allow multiple inputs to compare-failures

tools/gardening/lib/src/buildbot_structures.dart

Index: tools/gardening/lib/src/buildbot_structures.dart
diff --git a/tools/gardening/lib/src/buildbot_structures.dart b/tools/gardening/lib/src/buildbot_structures.dart
index 3e198b32361e91bce1ea0e9ce859c7e0cfebfd50..93bf0d70beb64755ea936e25a4cbccd96fb3c181 100644
--- a/tools/gardening/lib/src/buildbot_structures.dart
+++ b/tools/gardening/lib/src/buildbot_structures.dart
@@ -101,7 +101,7 @@ class TestConfiguration {
 
 /// The results of a build step.
 class BuildResult {
-  final BuildUri _buildUri;
+  final BuildUri buildUri;
 
   /// The absolute build number, if found.
   ///
@@ -114,12 +114,9 @@ class BuildResult {
   final List<TestFailure> _failures;
   final List<Timing> _timings;
 
-  BuildResult(this._buildUri, this.buildNumber, this._results, this._failures,
+  BuildResult(this.buildUri, this.buildNumber, this._results, this._failures,
       this._timings);
 
-  BuildUri get buildUri =>
-      buildNumber != null ? _buildUri.withBuildNumber(buildNumber) : _buildUri;
-
   /// `true` of the build result has test failures.
   bool get hasFailures => _failures.isNotEmpty;