refactor: drop object factory from execution context (#3099)

This patch:
- merges `ElementHandle` into `ExecutionContext` (for simplicity; there's no good reason to have them in separate files).
- removes the necessity to pass handle factory when creating `ExecutionContext`

This makes it easier to create execution contexts out of payloads.

References #1215

lib/FrameManager.js

@@ -17,8 +17,7 @@
 const fs = require('fs');
 const EventEmitter = require('events');
 const {helper, assert} = require('./helper');
-const {ExecutionContext, JSHandle} = require('./ExecutionContext');
-const {ElementHandle} = require('./ElementHandle');
+const {ExecutionContext} = require('./ExecutionContext');
 const {TimeoutError} = require('./Errors');
 
 const readFileAsync = helper.promisify(fs.readFile);
@@ -87,6 +86,13 @@ class FrameManager extends EventEmitter {
       this._handleFrameTree(child);
   }
 
+  /**
+   * @return {!Puppeteer.Page}
+   */
+  page() {
+    return this._page;
+  }
+
   /**
    * @return {!Frame}
    */
@@ -119,7 +125,7 @@ class FrameManager extends EventEmitter {
       return;
     assert(parentFrameId);
     const parentFrame = this._frames.get(parentFrameId);
-    const frame = new Frame(this._client, parentFrame, frameId);
+    const frame = new Frame(this, this._client, parentFrame, frameId);
     this._frames.set(frame._id, frame);
     this.emit(FrameManager.Events.FrameAttached, frame);
   }
@@ -146,7 +152,7 @@ class FrameManager extends EventEmitter {
         frame._id = framePayload.id;
       } else {
         // Initial main frame navigation.
-        frame = new Frame(this._client, null, framePayload.id);
+        frame = new Frame(this, this._client, null, framePayload.id);
       }
       this._frames.set(framePayload.id, frame);
       this._mainFrame = frame;
@@ -184,7 +190,7 @@ class FrameManager extends EventEmitter {
     const frameId = contextPayload.auxData ? contextPayload.auxData.frameId : null;
     const frame = this._frames.get(frameId) || null;
     /** @type {!ExecutionContext} */
-    const context = new ExecutionContext(this._client, contextPayload, obj => this.createJSHandle(context, obj), frame);
+    const context = new ExecutionContext(this._client, contextPayload, frame);
     this._contextIdToContext.set(contextPayload.id, context);
     if (frame)
       frame._addExecutionContext(context);
@@ -220,17 +226,6 @@ class FrameManager extends EventEmitter {
     return context;
   }
 
-  /**
-   * @param {!ExecutionContext} context
-   * @param {!Protocol.Runtime.RemoteObject} remoteObject
-   * @return {!JSHandle}
-   */
-  createJSHandle(context, remoteObject) {
-    if (remoteObject.subtype === 'node')
-      return new ElementHandle(context, this._client, remoteObject, this._page, this);
-    return new JSHandle(context, this._client, remoteObject);
-  }
-
   /**
    * @param {!Frame} frame
    */
@@ -259,17 +254,19 @@ FrameManager.Events = {
  */
 class Frame {
   /**
+   * @param {!FrameManager} frameManager
    * @param {!Puppeteer.CDPSession} client
    * @param {?Frame} parentFrame
    * @param {string} frameId
    */
-  constructor(client, parentFrame, frameId) {
+  constructor(frameManager, client, parentFrame, frameId) {
+    this._frameManager = frameManager;
     this._client = client;
     this._parentFrame = parentFrame;
     this._url = '';
     this._id = frameId;
 
-    /** @type {?Promise<!ElementHandle>} */
+    /** @type {?Promise<!Puppeteer.ElementHandle>} */
     this._documentPromise = null;
     /** @type {?Promise<!ExecutionContext>} */
     this._contextPromise = null;
@@ -350,7 +347,7 @@ class Frame {
 
   /**
    * @param {string} selector
-   * @return {!Promise<?ElementHandle>}
+   * @return {!Promise<?Puppeteer.ElementHandle>}
    */
   async $(selector) {
     const document = await this._document();
@@ -359,7 +356,7 @@ class Frame {
   }
 
   /**
-   * @return {!Promise<!ElementHandle>}
+   * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   async _document() {
     if (this._documentPromise)
@@ -373,7 +370,7 @@ class Frame {
 
   /**
    * @param {string} expression
-   * @return {!Promise<!Array<!ElementHandle>>}
+   * @return {!Promise<!Array<!Puppeteer.ElementHandle>>}
    */
   async $x(expression) {
     const document = await this._document();
@@ -406,7 +403,7 @@ class Frame {
 
   /**
    * @param {string} selector
-   * @return {!Promise<!Array<!ElementHandle>>}
+   * @return {!Promise<!Array<!Puppeteer.ElementHandle>>}
    */
   async $$(selector) {
     const document = await this._document();
@@ -476,7 +473,7 @@ class Frame {
 
   /**
    * @param {Object} options
-   * @return {!Promise<!ElementHandle>}
+   * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   async addScriptTag(options) {
     if (typeof options.url === 'string') {
@@ -542,7 +539,7 @@ class Frame {
 
   /**
    * @param {Object} options
-   * @return {!Promise<!ElementHandle>}
+   * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   async addStyleTag(options) {
     if (typeof options.url === 'string') {
@@ -878,7 +875,7 @@ class WaitTask {
 
   async rerun() {
     const runCount = ++this._runCount;
-    /** @type {?JSHandle} */
+    /** @type {?Puppeteer.JSHandle} */
     let success = null;
     let error = null;
     try {