DevTools: implement release note behind an experiment

third_party/WebKit/Source/devtools/front_end/help/ReleaseNoteManager.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.
+
+Help.ReleaseNoteManager = class {
+  /**
+   * @return {?Help.ReleaseNote}
+   */
+  static getCurrentVersionReleaseNote() {
+    var chromeRegex = new RegExp('(?:^|\\W)Chrome/(\\S+)');
+    var chromeMatch = navigator.userAgent.match(chromeRegex);
+    if (!chromeMatch || chromeMatch.length < 2)
+      return null;
+    var chromeVersion = parseInt(chromeMatch[1].split('.')[0], 10);
+    for (var note of Help.ReleaseNoteManager._releaseNotesByVersion) {
+      if (note.version === chromeVersion)
+        return note;
+    }

[luoe, 2017/02/11 00:30:54]

How about something shorter?
return _releaseNotesByVersion.find(note => note.version === chromeVersion)

+    return null;
+  }
+
+  constructor() {
+    this._timeoutDuration = 500;
+    // Only start showing release notes v58 and onwards
+    this._versionSetting = Common.settings.createSetting('releaseNoteVersionSeen', 57, false);
+  }
+
+  /**
+   * @return {?SDK.ConsoleMessage}
+   */
+  maybeGetReleaseNote() {
+    if (!Runtime.experiments.isEnabled('releaseNote'))
+      return null;
+    var chromeRegex = new RegExp('(?:^|\\W)Chrome/(\\S+)');
+    var chromeMatch = navigator.userAgent.match(chromeRegex);
+    if (!chromeMatch || chromeMatch.length < 2)
+      return null;
+    var chromeVersion = parseInt(chromeMatch[1].split('.')[0], 10);
+    var lastVersionSeen = this._versionSetting.get();
+    var note = this._getReleaseNote(chromeVersion, lastVersionSeen);
+    if (!note)
+      return null;
+    return this._releaseNoteConsoleMessage(note);
+  }
+
+  /**
+   * @param {number} version
+   */
+  sawReleaseNote(version) {
+    this._versionSetting.set(version);
+  }
+
+  /**
+   * @param {number} browserVersion
+   * @param {number} lastVersionSeen
+   * @return {?Help.ReleaseNote}
+   */
+  _getReleaseNote(browserVersion, lastVersionSeen) {
+    for (var note of Help.ReleaseNoteManager._releaseNotesByVersion) {
+      if (note.version > lastVersionSeen && note.version === browserVersion) {
+        note.timeout = this._timeoutDuration;

[luoe, 2017/02/11 00:30:54]

In the future, other assistance elements besides release notes could probably
benefit from the same if-hidden-before-timeout-don't-count-as-viewed logic. 
Could we move the intersectionObserver logic into this file and have the
releaseNotesManager manage it?

this._timeoutDuration is only used here.  Let's inline it or make a const.

"_getReleaseNote()" sounds like it just fetches and returns something.  Can we
move the set-Timeout into the individual call sites?

+        return note;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * @param {!Help.ReleaseNote} note
+   * @return {!SDK.ConsoleMessage}
+   */
+  _releaseNoteConsoleMessage(note) {
+    var messageText = 'Release Notes';
+    return new SDK.ConsoleMessage(
+        SDK.targetManager.mainTarget(), SDK.ConsoleMessage.MessageSource.Other, SDK.ConsoleMessage.MessageLevel.Note,
+        messageText, SDK.ConsoleMessage.MessageType.Log, undefined, undefined, undefined, undefined, [{
+          type: 'releaseNote',
+          objectId: 'releaseNote',
+          description: JSON.stringify(note),
+        }],
+        undefined, /* timestamp */ 1);
+  }
+
+  /**
+   * @param {number} version
+   * @return {?SDK.ConsoleMessage}
+   */
+  _showReleaseNoteByVersionForTesting(version) {
+    var browserVersion = version || 57;
+    var lastVersionSeen = browserVersion - 1;
+    var note = this._getReleaseNote(browserVersion, lastVersionSeen);
+    if (!note)
+      return null;
+    return this._releaseNoteConsoleMessage(note);
+  }
+};
+
+// 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)
+
+/** @typedef {!{src: string}} */
+Help.ReleaseNoteImage;
+
+/** @typedef {!{text: string, link: string, featured: (boolean | undefined)}} */
+Help.ReleaseNoteHighlight;
+
+/** @typedef {!{version: number, highlights: !Array<!Help.ReleaseNoteHighlight>, link: string, image: !Help.ReleaseNoteImage}} */
+Help.ReleaseNote;
+
+/** @type {!Array<!Help.ReleaseNote>} */
+Help.ReleaseNoteManager._releaseNotesByVersion = [

[luoe, 2017/02/11 00:30:54]

Can we move this data object into its own file?

[chenwilliam, 2017/02/15 00:57:08]

Done.

+  {
+    version: 57,
+    highlights: [
+      {
+        text: 'Re-designed Performance panel',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+        featured: true,
+      },
+      {
+        text: 'Inline breakpoints',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+      },
+      {
+        text: 'Better async debugging',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+      },
+      {
+        text: 'Node.js debugging is stable',
+        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',
+    },
+  },
+  {
+    version: 58,
+    highlights: [
+      {
+        text: 'Highlight #1',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+        featured: true,
+      },
+      {
+        text: 'Highlight #2',
+        link: 'https://developers.google.com/web/updates/2016/06/devtools-digest',
+      },
+      {
+        text: 'Highlight #3',
+        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',
+    },
+  }
+];
+
+/**
+ * @implements {UI.ActionDelegate}
+ */
+Help.ReleaseNoteManager.ActionDelegate = class {
+  /**
+   * @override
+   * @param {!UI.Context} context
+   * @param {string} actionId
+   * @return {boolean}
+   */
+  handleAction(context, actionId) {
+    if (actionId === 'help.release-notes') {
+      var link = Help.ReleaseNoteManager.getCurrentVersionReleaseNote().link;

[luoe, 2017/02/11 00:30:54]

getCurrentVersionReleaseNote() may be null

+      InspectorFrontendHost.openInNewTab(link);
+      return true;
+    }
+    return false;
+  }
+};