Fill in descriptions on relevant blink_perf tests

PerformanceTests/Parser/html-parser.html

Index: PerformanceTests/Parser/html-parser.html
diff --git a/PerformanceTests/Parser/html-parser.html b/PerformanceTests/Parser/html-parser.html
index 2c35d5d43bec529b5723cbf14595a5f3d7438578..db6da95096702050ba9c8fa7697ac68e7024014b 100644
--- a/PerformanceTests/Parser/html-parser.html
+++ b/PerformanceTests/Parser/html-parser.html
@@ -4,16 +4,19 @@
 <script>
 var spec = PerfTestRunner.loadFile("resources/html5.html");
 
-PerfTestRunner.measureTime({run: function() {
-    var iframe = document.createElement("iframe");
-    iframe.style.display = "none";  // Prevent creation of the rendering tree, so we only test HTML parsing.
-    iframe.sandbox = 'allow-same-origin';  // Prevent external script loads which could cause write() to return before completing the parse.
-    document.body.appendChild(iframe);
-    iframe.contentDocument.open();
-    iframe.contentDocument.write(spec);
-    iframe.contentDocument.close();
-    document.body.removeChild(iframe);
-}});
+PerfTestRunner.measureTime({
+    description: "Measures performance of the HTML parser.",
+    run: function() {
+        var iframe = document.createElement("iframe");
+        iframe.style.display = "none";  // Prevent creation of the rendering tree, so we only test HTML parsing.
+        iframe.sandbox = 'allow-same-origin';  // Prevent external script loads which could cause write() to return before completing the parse.
+        document.body.appendChild(iframe);
+        iframe.contentDocument.open();
+        iframe.contentDocument.write(spec);
+        iframe.contentDocument.close();
+        document.body.removeChild(iframe);
+    }
+});
 
 </script>
 </body>