Fill in descriptions on relevant blink_perf tests

PerformanceTests/Parser/url-parser.html

Index: PerformanceTests/Parser/url-parser.html
diff --git a/PerformanceTests/Parser/url-parser.html b/PerformanceTests/Parser/url-parser.html
index cee3e8cf2e301f3fe5f7b8227b87e5267a8d725d..44436143fb23e5d4bca70072909d4d25c657db8f 100644
--- a/PerformanceTests/Parser/url-parser.html
+++ b/PerformanceTests/Parser/url-parser.html
@@ -5,10 +5,13 @@
 var urls = PerfTestRunner.loadFile("resources/final-url-en").split("\n");
 var anchor = document.createElement("a");
 
-PerfTestRunner.measureRunsPerSecond({run:function() {
-    for (var x = 0; x < urls.length; x++) {
-        anchor.href = urls[x];
+PerfTestRunner.measureRunsPerSecond({
+    description: "Measures performance of URL parsing by setting the href attribute on an <a> tag to many different URLs.",
+    run: function() {
+        for (var x = 0; x < urls.length; x++) {
+            anchor.href = urls[x];
+        }
     }
-}});
+});
 </script>
 </body>