[js] Replace the awkward serializable interface with a symbol-based a…

…pproach

javascript/node/selenium-webdriver/chrome.js

@@ -123,7 +123,7 @@ const executors = require('./executors'),
     Capabilities = require('./lib/capabilities').Capabilities,
     Capability = require('./lib/capabilities').Capability,
     promise = require('./lib/promise'),
-    serializable = require('./lib/serializable'),
+    Symbols = require('./lib/symbols'),
     webdriver = require('./lib/webdriver'),
     portprober = require('./net/portprober'),
     remote = require('./remote');
@@ -369,7 +369,6 @@ let OPTIONS_CAPABILITY_KEY = 'chromeOptions';
 
 /**
  * Class for managing ChromeDriver specific options.
- * @implements serializable.Serializable
  */
 class Options {
   constructor() {
@@ -735,9 +734,8 @@ class Options {
    *           logPath: (string|undefined),
    *           prefs: (Object|undefined)}} The JSON wire protocol representation
    *     of this instance.
-   * @override
    */
-  serialize() {
+  [Symbols.serialize]() {
     let json = {};
     for (let key in this.options_) {
       if (this.options_[key] != null) {
@@ -756,7 +754,6 @@ class Options {
     return json;
   }
 }
-serializable.setSerializable(Options);
 
 
 /**

javascript/node/selenium-webdriver/edge.js

@@ -76,7 +76,7 @@ const fs = require('fs'),
 const executors = require('./executors'),
     io = require('./io'),
     capabilities = require('./lib/capabilities'),
-    serializable = require('./lib/serializable'),
+    Symbols = require('./lib/symbols'),
     webdriver = require('./lib/webdriver'),
     portprober = require('./net/portprober'),
     remote = require('./remote');
@@ -95,7 +95,6 @@ const CAPABILITY_KEY = {
 
 /**
  * Class for managing MicrosoftEdgeDriver specific options.
- * @implements {serializable.Serializable}
  */
 class Options {
   constructor() {
@@ -176,9 +175,8 @@ class Options {
    * function is an implementation not intended for general use.
    * @return {{pageLoadStrategy: (string|undefined)}
    *   The JSON wire protocol representation of this instance.
-   * @override
    */
-  serialize() {
+  [Symbols.serialize]() {
     var json = {};
     for (var key in this.options_) {
       if (this.options_[key] != null) {
@@ -188,7 +186,6 @@ class Options {
     return json;
   }
 }
-serializable.setSerializable(Options);
 
 
 /**

javascript/node/selenium-webdriver/firefox/binary.js

@@ -28,8 +28,8 @@ const child = require('child_process'),
     util = require('util');
 
 const isDevMode = require('../lib/devmode'),
-    serializable = require('../lib/serializable'),
     promise = require('../lib/promise'),
+    Symbols = require('../lib/symbols'),
     io = require('../io'),
     exec = require('../io/exec');
 
@@ -136,7 +136,6 @@ function installNoFocusLibs(profileDir) {
  * Provides a mechanism to configure and launch Firefox in a subprocess for
  * use with WebDriver.
  *
- * @implements {serializable.Serializable<string>}
  * @final
  */
 class Binary {
@@ -208,13 +207,11 @@ class Binary {
    *
    * @return {!promise.Promise<string>} A promise for this binary's wire
    *     representation.
-   * @override
    */
-  serialize() {
+  [Symbols.serialize]() {
     return promise.fulfilled(this.exe_ || findFirefox());
   }
 }
-serializable.setSerializable(Binary);
 
 
 // PUBLIC API

javascript/node/selenium-webdriver/firefox/profile.js

@@ -29,8 +29,8 @@ const AdmZip = require('adm-zip'),
     vm = require('vm');
 
 const isDevMode = require('../lib/devmode'),
-    serializable = require('../lib/serializable'),
     promise = require('../lib/promise'),
+    Symbols = require('../lib/symbols'),
     io = require('../io'),
     extension = require('./extension');
 
@@ -207,7 +207,6 @@ function decode(data) {
  * Models a Firefox proifle directory for use with the FirefoxDriver. The
  * {@code Proifle} directory uses an in-memory model until {@link #writeToDisk}
  * is called.
- * @implements {serializable.Serializable<string>}
  */
 class Profile {
   /**
@@ -391,13 +390,11 @@ class Profile {
   /**
    * Encodes this profile as a zipped, base64 encoded directory.
    * @return {!promise.Promise<string>} A promise for the encoded profile.
-   * @override
    */
-  serialize() {
+  [Symbols.serialize]() {
     return this.encode();
   }
 }
-serializable.setSerializable(Profile);
 
 
 // PUBLIC API

javascript/node/selenium-webdriver/index.js

@@ -32,7 +32,6 @@ const events = require('./lib/events');
 const input = require('./lib/input');
 const logging = require('./lib/logging');
 const promise = require('./lib/promise');
-const serializable = require('./lib/serializable');
 const session = require('./lib/session');
 const until = require('./lib/until');
 const webdriver = require('./lib/webdriver');
@@ -48,7 +47,6 @@ exports.Capability = capabilities.Capability;
 exports.EventEmitter = events.EventEmitter;
 exports.FileDetector = input.FileDetector;
 exports.Key = input.Key;
-exports.Serializable = serializable.Serializable;
 exports.Session = session.Session;
 exports.WebDriver = webdriver.WebDriver;
 exports.WebElement = webdriver.WebElement;

javascript/node/selenium-webdriver/lib/capabilities.js

@@ -22,7 +22,7 @@
  * WebDriver session.
  */
 
-const serializable = require('./serializable');
+const Symbols = require('./symbols');
 
 
 /**
@@ -172,8 +172,6 @@ function toMap(hash) {
 
 /**
  * Describes a set of capabilities for a WebDriver session.
- *
- * @implements {serializable.Serializable<!Object<string, ?>>}
  */
 class Capabilities extends Map {
   /**
@@ -283,9 +281,8 @@ class Capabilities extends Map {
   /**
    * @return {!Object<string, ?>} The JSON representation of this instance.
    *     Note, the returned object may contain nested promised values.
-   * @override
    */
-  serialize() {
+  [Symbols.serialize]() {
     let ret = {};
     for (let key of this.keys()) {
       let cap = this.get(key);
@@ -384,7 +381,6 @@ class Capabilities extends Map {
     return this.set(Capability.UNEXPECTED_ALERT_BEHAVIOR, behavior);
   }
 }
-serializable.setSerializable(Capabilities);
 
 
 // PUBLIC API

javascript/node/selenium-webdriver/lib/symbols.js

@@ -0,0 +1,36 @@
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+'use strict';
+
+/**
+ * @fileoverview Defines well-known symbols used within the selenium-webdriver
+ * library.
+ */
+
+
+/**
+ * The serialize symbol specifies a method that returns an object's serialized
+ * representation. If an object's serialized form is not immediately available,
+ * the serialize method will return a promise that will be resolved with the
+ * serialized form.
+ *
+ * Note that the described method is analgous to objects that define a
+ * `toJSON()` method, except the serialized result may be a promise, or another
+ * object with a promised property.
+ */
+exports.serialize = Symbol('serialize');

javascript/node/selenium-webdriver/lib/webdriver.js

@@ -28,8 +28,8 @@ const Capabilities = require('./capabilities').Capabilities;
 const command = require('./command');
 const input = require('./input');
 const logging = require('./logging');
-const serializable = require('./serializable');
 const Session = require('./session').Session;
+const Symbols = require('./symbols');
 const promise = require('./promise');
 const until = require('./until');
 
@@ -92,9 +92,8 @@ function executeCommand(executor, command) {
  * <ol>
  * <li>if the object is a WebElement, the return value will be the element's
  *     server ID
- * <li>if the object is a Serializable, its
- *     {@link serializable.Serializable#serialize} function will be invoked and
- *     this algorithm will recursively be applied to the result
+ * <li>if the object defines a {@link Symbols.serialize} method, this algorithm
+ *     will be recursively applied to the object's serialized representation
  * <li>if the object provides a "toJSON" function, this algorithm will
  *     recursively be applied to the result of that function
  * <li>otherwise, the value of each key will be recursively converted according
@@ -132,8 +131,8 @@ function convertValue(value) {
     return '' + value;
   }
 
-  if (serializable.isSerializable(value)) {
-    return toWireValue(value.serialize());
+  if (typeof value[Symbols.serialize] === 'function') {
+    return toWireValue(value[Symbols.serialize]());
   } else if (typeof value.toJSON === 'function') {
     return toWireValue(value.toJSON());
   }
@@ -1523,8 +1522,6 @@ const ELEMENT_ID_KEY = 'element-6066-11e4-a52e-4f735466cecf';
  *     var searchForm = driver.findElement(By.tagName('form'));
  *     var searchBox = searchForm.findElement(By.name('q'));
  *     searchBox.sendKeys('webdriver');
- *
- * @implements {serializable.Serializable}
  */
 class WebElement {
   /**
@@ -1624,8 +1621,10 @@ class WebElement {
     return this.getId();
   }
 
-  /** @override */
-  serialize() {
+  /**
+   * @return {!Object} Returns the serialized representation of this WebElement.
+   */
+  [Symbols.serialize]() {
     return this.getId().then(WebElement.buildId);
   }
 
@@ -2044,7 +2043,6 @@ class WebElement {
     return this.driver_.executeScript('return arguments[0].innerHTML', this);
   }
 }
-serializable.setSerializable(WebElement);
 
 
 /**