Change Numeric sourceInfos into sample diagnostics

tracing/tracing/metrics/system_health/first_paint_metric.html

Index: tracing/tracing/metrics/system_health/first_paint_metric.html
diff --git a/tracing/tracing/metrics/system_health/first_paint_metric.html b/tracing/tracing/metrics/system_health/first_paint_metric.html
index f2edb908f076cba6d567a5188e286dcdbde51199..31eed384bbbe6a2f6bc4ead3098a3402244851a1 100644
--- a/tracing/tracing/metrics/system_health/first_paint_metric.html
+++ b/tracing/tracing/metrics/system_health/first_paint_metric.html
@@ -284,7 +284,7 @@ tr.exportTo('tr.metrics.sh', function() {
           return;
 
         var timeToEvent = ev.start - navigationStartEvent.start;
-        histogram.add(timeToEvent, {url: url});
+        histogram.add(timeToEvent, new tr.v.d.Generic({url: url}));
       }, this);
       values.addValue(new tr.v.NumericValue(
           metric.valueName, histogram,
@@ -362,7 +362,8 @@ tr.exportTo('tr.metrics.sh', function() {
         return;
       }
       var timeToFirstMeaningfulPaint = paintEvent.start - navigationStart.start;
-      firstMeaningfulPaintHistogram.add(timeToFirstMeaningfulPaint, {url: url});
+      firstMeaningfulPaintHistogram.add(timeToFirstMeaningfulPaint,
+          new tr.v.d.Generic({url: url}));
     }
 
     var layoutsForFrameId = findAllLayoutEvents(rendererHelper);