[telemetry] Add Html2OutputFormatter for generating results2.html

tracing/tracing/metrics/value_set.html

Index: tracing/tracing/metrics/value_set.html
diff --git a/tracing/tracing/metrics/value_set.html b/tracing/tracing/metrics/value_set.html
index 60d636146a8bae77347d802a3e336f4a21fd348d..e949176da282779b0dbfc8f9e5bf3cbb1d19a878 100644
--- a/tracing/tracing/metrics/value_set.html
+++ b/tracing/tracing/metrics/value_set.html
@@ -30,6 +30,14 @@ tr.exportTo('tr.metrics', function() {
       return tr.b.dictionaryValues(this.values_).map(cb, opt_this);
     },
 
+    addValueDicts: function(dicts) {
+      dicts.forEach(function(dict) {
+        var value = tr.v.Value.fromDict(dict);
+        this.addValue(value);
+        // TODO(TBMv2.1): Patch up RelatedValueSets here.
+      }, this);
+    },
+
     getValuesWithName: function(name) {
       return tr.b.dictionaryValues(this.values_).filter(function(value) {
         return value.name.indexOf(name) > -1;