Format traceUrls in generic-set-span.

tracing/tracing/base/utils.html

Index: tracing/tracing/base/utils.html
diff --git a/tracing/tracing/base/utils.html b/tracing/tracing/base/utils.html
index 77d3c8b17c7f6a5dba72abbcbff98098640e76d6..e2f6ba81b9d59264f711a0bdc810c29ba9e7df8e 100644
--- a/tracing/tracing/base/utils.html
+++ b/tracing/tracing/base/utils.html
@@ -11,7 +11,7 @@ found in the LICENSE file.
 'use strict';
 
 tr.exportTo('tr.b', function() {
-  const URL_REGEX = /^https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)$/;  // eslint-disable-line max-len
+  const URL_REGEX = /^(https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b|file:\/\/)([-a-zA-Z0-9@:%_\+.~#?&//=]*)$/;  // eslint-disable-line max-len
 
   function deepCopy(value) {
     if (!(value instanceof Object)) {