Add Server-Timing support to devtools

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

Index: third_party/WebKit/Source/devtools/front_end/sdk/ServerTiming.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/ServerTiming.js b/third_party/WebKit/Source/devtools/front_end/sdk/ServerTiming.js
new file mode 100644
index 0000000000000000000000000000000000000000..a744503e3a1917cb202e479b3d0de8484758a672
--- /dev/null
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/ServerTiming.js
@@ -0,0 +1,68 @@
+// 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;
+    this.metric = metric;
+    this.value = value;
+    this.description = description;
+}
+
+/**
+ * @param {!WebInspector.Target} target
+ * @param {!Array.<!WebInspector.NetworkRequest.NameValue>} headers

[caseq, 2016/04/05 17:18:42]

nit: here and below, please use Array<> instead of Array.<>

+ * @return {?Array.<!WebInspector.ServerTiming>}
+ */
+WebInspector.ServerTiming.parseHeaders = function(target, headers)
+{
+    var rawServerTimingHeaders = headers.filter(item => item.name.toLowerCase() === 'server-timing');

[caseq, 2016/04/05 17:18:42]

use "double quotes", please.

+    if (!rawServerTimingHeaders.length)
+        return null;
+    
+    /**
+     * @param {?string} valueString
+     * @return {?Array.<!WebInspector.ServerTiming>}
+     */
+    function createFromHeaderValue(valueString)
+    {
+        // Server-Timing = "Server-Timing" ":" #server-timing-metric

[caseq, 2016/04/05 17:18:42]

Should we have a link to the w3c doc here instead?

+        // server-timing-metric   = metric  [ ";" description ]
+        // metric                 = metric-name [ "=" metric-value ]
+        // metric-name            = token
+        // metric-value           = 1*digit [ "." 1*digit ]
+        // description            = token | quoted-string
+        // token                  = 1*tchar
+        // tchar                  = "!" / "#" / "$" / "%" / "&" / "'" / "*"
+        //                           / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
+        //                           / DIGIT / ALPHA
+        var serverTimingMetricRegExp = /[ \t]*([\!\#\$\%\&\'\*\+\-\.\^\_\`\|\~0-9A-Za-z]+)[ \t]*(?:=[ \t]*(\d+(?:\.\d+)?))?[ \t]*(?:;[ \t]*(?:"([^"]+)"|([\!\#\$\%\&\'\*\+\-\.\^\_\`\|\~0-9A-Za-z]+)))?[ \t]*(?:,(.*))?/;
+        var metricMatch, result = [];

[caseq, 2016/04/05 17:18:42]

style: please put result on a separate line.

+        while (valueString && (metricMatch = serverTimingMetricRegExp.exec(valueString))) {
+            var metric = metricMatch[1],
+                value = metricMatch[2],

[caseq, 2016/04/05 17:18:42]

style: please split into separate var statements.

+                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;
+}