Add Server-Timing support to devtools

third_party/WebKit/Source/devtools/front_end/sdk/ServerTiming.js

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @constructor
+ * @param {!WebInspector.Target} target
+ * @param {string} metric
+ * @param {number} value
+ * @param {string} description
+ */
+WebInspector.ServerTiming = function(target, metric, value, description)
+{
+    this._target = target;

[caseq, 2016/04/26 03:56:42]

why do we need target here?

+    this.metric = metric;
+    this.value = value;
+    this.description = description;
+}
+
+/**
+ * @param {!WebInspector.Target} target
+ * @param {!Array<!WebInspector.NetworkRequest.NameValue>} headers
+ * @return {?Array<!WebInspector.ServerTiming>}
+ */
+WebInspector.ServerTiming.parseHeaders = function(target, headers)
+{
+    var rawServerTimingHeaders = headers.filter(item => item.name.toLowerCase() === "server-timing");
+    if (!rawServerTimingHeaders.length)
+        return null;
+    
+    /**
+     * @param {?string} valueString
+     * @return {?Array<!WebInspector.ServerTiming>}
+     */
+    function createFromHeaderValue(valueString)
+    {
+        // https://www.w3.org/TR/server-timing/
+        var serverTimingMetricRegExp = /[ \t]*([\!\#\$\%\&\'\*\+\-\.\^\_\`\|\~0-9A-Za-z]+)[ \t]*(?:=[ \t]*(\d+(?:\.\d+)?))?[ \t]*(?:;[ \t]*(?:"([^"]+)"|([\!\#\$\%\&\'\*\+\-\.\^\_\`\|\~0-9A-Za-z]+)))?[ \t]*(?:,(.*))?/;
+        var metricMatch;
+        var result = [];
+        while (valueString && (metricMatch = serverTimingMetricRegExp.exec(valueString))) {
+            var metric = metricMatch[1];
+            var value = metricMatch[2];
+            var description = metricMatch[3] || metricMatch[4];
+            if (value !== null)
+                value = Math.abs(parseFloat(metricMatch[2]));
+            valueString = metricMatch[5]; // comma delimited headers
+            result.push(new WebInspector.ServerTiming(target, metric, value, description));
+        }
+        return result;
+    }
+    
+    var serverTimings = rawServerTimingHeaders.reduce((memo, header) => {
+        var timing = createFromHeaderValue(header.value);
+        Array.prototype.push.apply(memo, timing);
+        return memo;
+    }, []);
+    serverTimings.sort((a, b) => a.metric.toLowerCase().compareTo(b.metric.toLowerCase()));
+    return serverTimings;
+}