Define DiagnosticMap and a basic Diagnostic hierarchy

tracing/tracing/metrics/tracing_metric.html

Index: tracing/tracing/metrics/tracing_metric.html
diff --git a/tracing/tracing/metrics/tracing_metric.html b/tracing/tracing/metrics/tracing_metric.html
index b366aff294deb0a4825ed5b6f13e32a7c55960cb..f43881fdf452fc195284cbd119c5bb2c446bed75 100644
--- a/tracing/tracing/metrics/tracing_metric.html
+++ b/tracing/tracing/metrics/tracing_metric.html
@@ -88,28 +88,28 @@ tr.exportTo('tr.metrics', function() {
     var totalTraceBytesValue = new tr.v.ScalarNumeric(
         tr.v.Unit.byName.sizeInBytes_smallerIsBetter, totalTraceBytes);
 
-    var diagnostics = {
-      category_with_max_event_size: {
-        name: categoryWithMaxEventBytes,
-        size_in_bytes: maxEventBytesPerCategory
-      }
+    var biggestCategory = {
+      name: categoryWithMaxEventBytes,
+      size_in_bytes: maxEventBytesPerCategory
     };
 
-    values.addValue(new tr.v.NumericValue(
-        model.canonicalUrl,
-        'Total trace size in bytes',
-        totalTraceBytesValue,
-        undefined, undefined, diagnostics));
-    values.addValue(new tr.v.NumericValue(
-        model.canonicalUrl,
-        'Max number of events per second',
-        maxEventCountPerSecValue,
-        undefined, undefined, diagnostics));
-    values.addValue(new tr.v.NumericValue(
-        model.canonicalUrl,
-        'Max event size in bytes per second',
-        maxEventBytesPerSecValue,
-        undefined, undefined, diagnostics));
+    var totalBytes = new tr.v.NumericValue(
+        'Total trace size in bytes', totalTraceBytesValue);
+    totalBytes.diagnostics.add(
+        'category_with_max_event_size', new tr.v.d.Generic(biggestCategory));
+    values.addValue(totalBytes);
+
+    var peakEvents = new tr.v.NumericValue(
+        'Max number of events per second', maxEventCountPerSecValue);
+    peakEvents.diagnostics.add(
+        'category_with_max_event_size', new tr.v.d.Generic(biggestCategory));
+    values.addValue(peakEvents);
+
+    var peakBytes = new tr.v.NumericValue(
+        'Max event size in bytes per second', maxEventBytesPerSecValue);
+    peakBytes.diagnostics.add(
+        'category_with_max_event_size', new tr.v.d.Generic(biggestCategory));
+    values.addValue(peakBytes);
   }
 
   tr.metrics.MetricRegistry.register(tracingMetric);
@@ -117,6 +117,5 @@ tr.exportTo('tr.metrics', function() {
   return {
     tracingMetric: tracingMetric
   };
-
 });
 </script>