Refactor Histogram relationship diagnostics.

tracing/tracing/value/ui/diagnostic_span_behavior.html

Index: tracing/tracing/value/ui/diagnostic_span_behavior.html
diff --git a/tracing/tracing/value/ui/diagnostic_span_behavior.html b/tracing/tracing/value/ui/diagnostic_span_behavior.html
index a40c15cb1c8dab1614e284b8f3d7de872c325b83..ebc8c230dfecc8ae5bf4a9a5c7d73cd5b6a5ea8c 100644
--- a/tracing/tracing/value/ui/diagnostic_span_behavior.html
+++ b/tracing/tracing/value/ui/diagnostic_span_behavior.html
@@ -15,6 +15,7 @@ tr.exportTo('tr.v.ui', function() {
       this.diagnostic_ = undefined;
       this.name_ = undefined;
       this.histogram_ = undefined;
+      this.histograms_ = undefined;
     },
 
     attached() {
@@ -25,10 +26,17 @@ tr.exportTo('tr.v.ui', function() {
       return this.diagnostic_;
     },
 
-    build(diagnostic, name, histogram) {
+    /**
+     * @param {!tr.v.d.Diagnostic} diagnostic
+     * @param {string} name
+     * @param {!tr.v.Histogram} histogram
+     * @param {!tr.v.HistogramSet} histograms
+     */
+    build(diagnostic, name, histogram, histograms) {
       this.diagnostic_ = diagnostic;
       this.name_ = name;
       this.histogram_ = histogram;
+      this.histograms_ = histograms;
       if (this.isAttached) this.updateContents_();
     },