Refactor diagnostic spans to share a polymer behavior.

tracing/tracing/value/ui/collected_related_event_set_span.html

Index: tracing/tracing/value/ui/collected_related_event_set_span.html
diff --git a/tracing/tracing/value/ui/collected_related_event_set_span.html b/tracing/tracing/value/ui/collected_related_event_set_span.html
index 847d9d842748af3c8c7d8635af9b5b38af5dbb77..08e0cc91dcac80c8144f0d80e0eca9f9d9f180a2 100644
--- a/tracing/tracing/value/ui/collected_related_event_set_span.html
+++ b/tracing/tracing/value/ui/collected_related_event_set_span.html
@@ -5,26 +5,17 @@ Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
-<link rel="import" href="/tracing/ui/base/base.html">
+<link rel="import" href="/tracing/value/ui/diagnostic_span_behavior.html">
 
 <dom-module id="tr-v-ui-collected-related-event-set-span">
-  <script>
-  'use strict';
+</dom-module>
+
+<script>
+'use strict';
+tr.exportTo('tr.v.ui', function() {
   Polymer({
     is: 'tr-v-ui-collected-related-event-set-span',
-
-    ready() {
-      this.diagnostic_ = undefined;
-    },
-
-    get diagnostic() {
-      return this.diagnostic_;
-    },
-
-    set diagnostic(d) {
-      this.diagnostic_ = d;
-      this.updateContents_();
-    },
+    behaviors: [tr.v.ui.DIAGNOSTIC_SPAN_BEHAVIOR],
 
     updateContents_() {
       Polymer.dom(this).textContent = '';
@@ -43,5 +34,7 @@ found in the LICENSE file.
       }
     }
   });
-  </script>
-</dom-module>
+
+  return {};
+});
+</script>