Fix request interception corner cases (#261)

This patch:
- teaches request interception to ignore data URLs. Currently protocol
  doesn't send interceptions for data URLs.
- teaches request interception to properly process URLs with hashes.
  Currently `Network.requestIntercepted` sends url with a hash, whereas
  `Network.requestWillBeSent` doesn't report hashes in its urls. @see
  crbug.com/755456
- skips one more header that I spotted during debugging interception on
  the realworld websites.

Fixes #258, #259.

lib/NetworkManager.js

@@ -16,6 +16,7 @@
 const EventEmitter = require('events');
 const helper = require('./helper');
 const Multimap = require('./Multimap');
+const {URL} = require('url');
 
 class NetworkManager extends EventEmitter {
   /**
@@ -84,6 +85,9 @@ class NetworkManager extends EventEmitter {
    * @param {!Object} event
    */
   _onRequestIntercepted(event) {
+    // Strip out url hash to be consistent with requestWillBeSent. @see crbug.com/755456
+    event.request.url = removeURLHash(event.request.url);
+
     if (event.redirectStatusCode) {
       let request = this._interceptionIdToRequest.get(event.interceptionId);
       console.assert(request, 'INTERNAL ERROR: failed to find request for interception redirect.');
@@ -127,7 +131,7 @@ class NetworkManager extends EventEmitter {
    * @param {!Object} event
    */
   _onRequestWillBeSent(event) {
-    if (this._requestInterceptionEnabled) {
+    if (this._requestInterceptionEnabled && !event.request.url.startsWith('data:')) {
       // All redirects are handled in requestIntercepted.
       if (event.redirectResponse)
         return;
@@ -236,6 +240,9 @@ class Request {
    * @param {!Object=} overrides
    */
   continue(overrides = {}) {
+    // DataURL's are not interceptable. In this case, do nothing.
+    if (this.url.startsWith('data:'))
+      return;
     console.assert(this._interceptionId, 'Request Interception is not enabled!');
     console.assert(!this._interceptionHandled, 'Request is already handled!');
     this._interceptionHandled = true;
@@ -255,6 +262,9 @@ class Request {
   }
 
   abort() {
+    // DataURL's are not interceptable. In this case, do nothing.
+    if (this.url.startsWith('data:'))
+      return;
     console.assert(this._interceptionId, 'Request Interception is not enabled!');
     console.assert(!this._interceptionHandled, 'Request is already handled!');
     this._interceptionHandled = true;
@@ -338,13 +348,23 @@ function generateRequestHash(request) {
   let headers = Object.keys(request.headers);
   headers.sort();
   for (let header of headers) {
-    if (header === 'Accept' || header === 'Referer')
+    if (header === 'Accept' || header === 'Referer' || header === 'X-DevTools-Emulate-Network-Conditions-Client-Id')
       continue;
     hash.headers[header] = request.headers[header];
   }
   return JSON.stringify(hash);
 }
 
+/**
+ * @param {string} url
+ * @return {string}
+ */
+function removeURLHash(url) {
+  let urlObject = new URL(url);
+  urlObject.hash = '';
+  return urlObject.toString();
+}
+
 NetworkManager.Events = {
   Request: 'request',
   Response: 'response',