feat(Page): report 'Log' domain entries as 'console' events (#2400)

Fixes #1939

lib/Page.js

@@ -50,6 +50,7 @@ class Page extends EventEmitter {
       client.send('Runtime.enable', {}),
       client.send('Security.enable', {}),
       client.send('Performance.enable', {}),
+      client.send('Log.enable', {}),
     ]);
     if (ignoreHTTPSErrors)
       await client.send('Security.setOverrideCertificateErrors', {override: true});
@@ -103,7 +104,7 @@ class Page extends EventEmitter {
     client.on('Security.certificateError', event => this._onCertificateError(event));
     client.on('Inspector.targetCrashed', event => this._onTargetCrashed());
     client.on('Performance.metrics', event => this._emitMetrics(event));
-
+    client.on('Log.entryAdded', event => this._onLogEntryAdded(event));
     this._target._isClosedPromise.then(() => this.emit(Page.Events.Close));
   }
 
@@ -125,6 +126,14 @@ class Page extends EventEmitter {
     this.emit('error', new Error('Page crashed!'));
   }
 
+  _onLogEntryAdded(event) {
+    const {level, text, args} = event.entry;
+    if (args)
+      args.map(arg => helper.releaseObject(this._client, arg));
+
+    this.emit(Page.Events.Console, new ConsoleMessage(level, text));
+  }
+
   /**
    * @return {!Puppeteer.Frame}
    */
@@ -1048,7 +1057,7 @@ class ConsoleMessage {
    * @param {string} text
    * @param {!Array<*>} args
    */
-  constructor(type, text, args) {
+  constructor(type, text, args = []) {
     this._type = type;
     this._text = text;
     this._args = args;

test/page.spec.js

@@ -331,6 +331,15 @@ module.exports.addTests = function({testRunner, expect, puppeteer, DeviceDescrip
       ]);
       expect(message.text()).toBe('JSHandle@object');
     });
+    it('should trigger correct Log', async({page, server}) => {
+      await page.goto('about:blank');
+      let message;
+      page.on('console', event => message = event);
+      page.evaluate(async url => fetch(url).catch(e => {}), server.EMPTY_PAGE);
+      await waitEvent(page, 'console');
+      expect(message.text()).toContain('No \'Access-Control-Allow-Origin\'');
+      expect(message.type()).toEqual('error');
+    });
   });
 
   describe('Page.Events.DOMContentLoaded', function() {