Change getAccessToken and getExtensionPrinterAccess to sendWithPromise

chrome/browser/resources/print_preview/cloud_print_interface.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.exportPath('cloudprint');
 
 /**
  * Event types dispatched by the cloudprint interface.
  * @enum {string}
  */
@@ skipping 83 matching lines @@
     this.requestQueue_ = [];
 
     /**
      * Outstanding cloud destination search requests.
      * @type {!Array<!cloudprint.CloudPrintRequest>}
      * @private
      */
     this.outstandingCloudSearchRequests_ = [];
 
     /**
-     * Event tracker used to keep track of native layer events.
-     * @type {!EventTracker}
-     * @private
+     * Promise that will be resolved when the access token for
+     * DestinationOrigin.DEVICE is available. Null if there is no request
+     * currently pending.
+     * @private {?Promise}
      */
-    this.tracker_ = new EventTracker();
+    this.accessTokenRequestPromise_ = null;
 
-    this.addEventListeners_();
   }
 
   /**
    * Content type header value for a URL encoded HTTP request.
    * @type {string}
    * @const
    * @private
    */
   CloudPrintInterface.URL_ENCODED_CONTENT_TYPE_ =
       'application/x-www-form-urlencoded';
@@ skipping 35 matching lines @@
 
   /**
    * Could Print origins used to search printers.
    * @type {!Array<!print_preview.DestinationOrigin>}
    * @const
    * @private
    */
   CloudPrintInterface.CLOUD_ORIGINS_ = [
     print_preview.DestinationOrigin.COOKIES,
     print_preview.DestinationOrigin.DEVICE
-    // TODO(vitalybuka): Enable when implemented.
-    // ready print_preview.DestinationOrigin.PROFILE
   ];
 
   CloudPrintInterface.prototype = {
     __proto__: cr.EventTarget.prototype,
 
     /** @return {string} Base URL of the Google Cloud Print service. */
     get baseUrl() {
       return this.baseUrl_;
     },
 
@@ skipping 131 matching lines @@
       var params = [
         new HttpParam('printerid', printerId), new HttpParam('use_cdd', 'true'),
         new HttpParam('printer_connection_status', 'true')
       ];
       this.sendOrQueueRequest_(this.buildRequest_(
           'GET', 'printer', params, origin, account || '',
           this.onPrinterDone_.bind(this, printerId)));
     },
 
     /**
-     * Adds event listeners to relevant events.
-     * @private
-     */
-    addEventListeners_: function() {
-      this.tracker_.add(
-          this.nativeLayer_.getEventTarget(),
-          print_preview.NativeLayer.EventType.ACCESS_TOKEN_READY,
-          this.onAccessTokenReady_.bind(this));
-    },
-
-    /**
      * Builds request to the Google Cloud Print API.
      * @param {string} method HTTP method of the request.
      * @param {string} action Google Cloud Print action to perform.
      * @param {Array<!HttpParam>} params HTTP parameters to include in the
      *     request.
      * @param {!print_preview.DestinationOrigin} origin Origin for destination.
      * @param {?string} account Account the request is sent for. Can be
      *     {@code null} or empty string if the request is not cookie bound or
      *     is sent on behalf of the primary user.
      * @param {function(!cloudprint.CloudPrintRequest)} callback Callback to
@@ skipping 53 matching lines @@
           xhr, body, origin, account, callback);
     },
 
     /**
      * Sends a request to the Google Cloud Print API or queues if it needs to
      *     wait OAuth2 access token.
      * @param {!cloudprint.CloudPrintRequest} request Request to send or queue.
      * @private
      */
     sendOrQueueRequest_: function(request) {
-      if (request.origin == print_preview.DestinationOrigin.COOKIES) {
+      if (request.origin == print_preview.DestinationOrigin.COOKIES)
         return this.sendRequest_(request);

[dpapad, 2017/06/20 16:09:09]

This method is not declaring any @return. Should this be

if (request.origin == print_preview.DestinationOrigin.COOKIES) {
  this.sendRequest_(request);
  return;
}

[rbpotter, 2017/06/21 03:52:28]

I suspect this was done since sendRequest_ does not return anything,
but agree this is more clear. Done.

-      } else {
-        this.requestQueue_.push(request);
-        this.nativeLayer_.startGetAccessToken(request.origin);
-      }
+
+      this.requestQueue_.push(request);

[dpapad, 2017/06/20 16:09:09]

So, is the requestQueue_ necessary anymore? I think we can remove as follows,
WDYT?

Per my understanding this was used to queue a print request, until the
ACCESS_TOKEN_READY event was fired. Once fired, the list was being searched for
the correct authType (not relevant anymore) and a request was sent to the cloud
print API.

Now that we have the Promise, we don't need to queue, all we need to do is to
wait for the Promise.

sendOrQueueRequest_: function(request) {
  if (request.origin == print_preview.DestinationOrigin.COOKIES) {
    this.sendRequest_(request);
    return;
  }

  if (this.accessTokenRequestPromise_ == null) {
    this.accessTokenRequestPromise_ = 
        this.nativeLayer_.getAccessToken(request.origin);
  }

  this.accessTokenRequestPromise_.then(
      this.onAccessTokenReady_.bind(this, request));
}

onAccessTokenReady_: function (request, accessToken) {
  if (accessToken) {
    ...
  } else {
    ...
  }
  this.accessTokenRequestPromise_ = null;
}

[rbpotter, 2017/06/21 03:52:28]

Done. Queue is not needed anymore, thanks for the suggestion.

+      if (this.accessTokenRequestPromise_ != null)
+        return;
+
+      this.accessTokenRequestPromise_ =
+          this.nativeLayer_.getAccessToken(request.origin).then(
+              this.onAccessTokenReady_.bind(this));
     },
 
     /**
      * Sends a request to the Google Cloud Print API.
      * @param {!cloudprint.CloudPrintRequest} request Request to send.
      * @private
      */
     sendRequest_: function(request) {
       request.xhr.onreadystatechange =
           this.onReadyStateChange_.bind(this, request);
@@ skipping 51 matching lines @@
           this.outstandingCloudSearchRequests_.filter(function(request) {
             if (origins.indexOf(request.origin) >= 0) {
               request.xhr.abort();
               return false;
             }
             return true;
           });
     },
 
     /**
-     * Called when a native layer receives access token.
-     * @param {Event} event Contains the authentication type and access token.
+     * Called when a native layer receives access token. Assumes that the
+     * destination type for this token is DestinationOrigin.DEVICE.
+     * @param {string} accessToken The access token obtained.
      * @private
      */
-    onAccessTokenReady_: function(event) {
-      // TODO(vitalybuka): remove when other Origins implemented.
-      assert(event.authType == print_preview.DestinationOrigin.DEVICE);
-      this.requestQueue_ = this.requestQueue_.filter(function(request) {
+    onAccessTokenReady_: function(accessToken) {
+      this.requestQueue_ = this.requestQueue_.forEach(function(request) {
         assert(request.origin == print_preview.DestinationOrigin.DEVICE);
-        if (request.origin != event.authType) {
-          return true;
-        }
-        if (event.accessToken) {
+        if (accessToken) {
           request.xhr.setRequestHeader(
-              'Authorization', 'Bearer ' + event.accessToken);
+              'Authorization', 'Bearer ' + accessToken);
           this.sendRequest_(request);
         } else {  // No valid token.
           // Without abort status does not exist.
           request.xhr.abort();
           request.callback(request);
         }
-        return false;
       }, this);
+      this.requestQueue_ = [];
+      this.accessTokenRequestPromise_ = null;
     },
 
     /**
      * Called when the ready-state of a XML http request changes.
      * Calls the successCallback with the result or dispatches an ERROR event.
      * @param {!cloudprint.CloudPrintRequest} request Request that was changed.
      * @private
      */
     onReadyStateChange_: function(request) {
       if (request.xhr.readyState == 4) {
@@ skipping 276 matching lines @@
      */
     this.value = value;
   }
 
   // Export
   return {
     CloudPrintInterface: CloudPrintInterface,
     CloudPrintRequest: CloudPrintRequest
   };
 });