chore(types): upgrade to TypeScript 2.8.1 (#2304)

This converts `externs.d.ts` to export a global namespace instead of a UMD global.

See: https://github.com/Microsoft/TypeScript/issues/22969

Fixes #2279.

lib/Puppeteer.js

@@ -17,7 +17,7 @@ const {helper} = require('./helper');
 const Launcher = require('./Launcher');
 const BrowserFetcher = require('./BrowserFetcher');
 
-class Puppeteer {
+module.exports = class {
   /**
    * @param {!Object=} options
    * @return {!Promise<!Puppeteer.Browser>}
@@ -55,7 +55,6 @@ class Puppeteer {
   static createBrowserFetcher(options) {
     return new BrowserFetcher(options);
   }
-}
+};
 
-module.exports = Puppeteer;
-helper.tracePublicAPI(Puppeteer);
+helper.tracePublicAPI(module.exports, 'Puppeteer');

lib/externs.d.ts

@@ -9,37 +9,40 @@ import {JSHandle as RealJSHandle, ExecutionContext as RealExecutionContext}  fro
 import * as RealElementHandle  from './ElementHandle.js';
 import { NetworkManager as RealNetworkManager, Request as RealRequest, Response as RealResponse } from './NetworkManager.js';
 import * as child_process from 'child_process';
-export as namespace Puppeteer;
+declare global {
+  module Puppeteer {
+    export class Connection extends RealConnection {}
+    export class CDPSession extends RealCDPSession {}
+    export class Mouse extends RealMouse {}
+    export class Keyboard extends RealKeyboard {}
+    export class Touchscreen extends RealTouchscreen {}
+    export class TaskQueue extends RealTaskQueue {}
+    export class Browser extends RealBrowser {}
+    export class Target extends RealTarget {}
+    export class Frame extends RealFrame {}
+    export class FrameManager extends RealFrameManager {}
+    export class NetworkManager extends RealNetworkManager {}
+    export class ElementHandle extends RealElementHandle {}
+    export class JSHandle extends RealJSHandle {}
+    export class ExecutionContext extends RealExecutionContext {}
+    export class Page extends RealPage { }
+    export class Response extends RealResponse { }
+    export class Request extends RealRequest { }
 
-export class Connection extends RealConnection {}
-export class CDPSession extends RealCDPSession {}
-export class Mouse extends RealMouse {}
-export class Keyboard extends RealKeyboard {}
-export class Touchscreen extends RealTouchscreen {}
-export class TaskQueue extends RealTaskQueue {}
-export class Browser extends RealBrowser {}
-export class Target extends RealTarget {}
-export class Frame extends RealFrame {}
-export class FrameManager extends RealFrameManager {}
-export class NetworkManager extends RealNetworkManager {}
-export class ElementHandle extends RealElementHandle {}
-export class JSHandle extends RealJSHandle {}
-export class ExecutionContext extends RealExecutionContext {}
-export class Page extends RealPage { }
-export class Response extends RealResponse { }
-export class Request extends RealRequest { }
+    export interface ConnectionTransport extends NodeJS.EventEmitter {
+      send(string);
+      close();
+    }
 
-export interface ConnectionTransport extends NodeJS.EventEmitter {
-  send(string);
-  close();
-}
+    export interface TargetInfo {
+      type: string;
+      targetId: string;
+      title: string;
+      url: string;
+      attached: boolean;
+    }
 
-export interface TargetInfo {
-  type: string;
-  targetId: string;
-  title: string;
-  url: string;
-  attached: boolean;
-}
+    export interface ChildProcess extends child_process.ChildProcess {}
 
-export interface ChildProcess extends child_process.ChildProcess {}
+  }
+}

lib/helper.js

@@ -112,9 +112,10 @@ class Helper {
 
   /**
    * @param {!Object} classType
+   * @param {string=} publicName
    */
-  static tracePublicAPI(classType) {
-    let className = classType.prototype.constructor.name;
+  static tracePublicAPI(classType, publicName) {
+    let className = publicName || classType.prototype.constructor.name;
     className = className.substring(0, 1).toLowerCase() + className.substring(1);
     const debug = require('debug')(`puppeteer:${className}`);
     if (!debug.enabled && !apiCoverage)