DevTools: implement release note behind an experiment

third_party/WebKit/Source/devtools/front_end/help/ReleaseNoteText.js

+// Copyright 2017 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.
+
+// NOTE: need to be careful about adding release notes early otherwise it'll
+// be shown in Canary (e.g. make sure the release notes are accurate).
+// https://github.com/ChromeDevTools/devtools-frontend/wiki/Release-Notes
+
+/** @type {!Array<!Help.ReleaseNote>} */
+Help.releaseNoteText = [
+  {
+    version: 58,
+    highlights: [
+      {
+        text: 'Review CSS changes in the new Changes drawer',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+        featured: true,
+      },
+      {
+        text: 'Contextual icons in Console',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+      },
+      {
+        text: 'Release notes for DevTools',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+      },
+    ],
+    link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+    image: {
+      src: 'https://developers.google.com/web/updates/images/2016/08/colorpicker.jpg',
+    },
+  },
+];