Print Preview: change getPreview to cr.sendWithPromise

chrome/browser/resources/print_preview/preview_generator.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.define('print_preview', function() {
   'use strict';
 
   /**
    * Interface to the Chromium print preview generator.
    * @param {!print_preview.DestinationStore} destinationStore Used to get the
@@ skipping 155 matching lines @@
     // Dispatched when the current print preview request fails.
     FAIL: 'print_preview.PreviewGenerator.FAIL'
   };
 
   PreviewGenerator.prototype = {
     __proto__: cr.EventTarget.prototype,
 
     /**
      * Request that new preview be generated. A preview request will not be
      * generated if the print ticket has not changed sufficiently.
-     * @return {boolean} Whether a new preview was actually requested.
+     * @return {{id: number,
+     *           request: Promise}} The preview request id, or -1 if no preview
+     *     was requested, and a promise that will resolve when the preview is
+     *     complete (null if no preview was actually requested).
      */
     requestPreview: function() {
       if (!this.printTicketStore_.isTicketValidForPreview() ||
           !this.printTicketStore_.isInitialized ||
           !this.destinationStore_.selectedDestination) {
-        return false;
+        return {id: -1, request: null};
       }
       var previewChanged = this.hasPreviewChanged_();
       if (!previewChanged && !this.hasPreviewPageRangeChanged_()) {
         // Changes to these ticket items might not trigger a new preview, but
         // they still need to be recorded.
         this.marginsType_ = this.printTicketStore_.marginsType.getValue();
-        return false;
+        return {id: -1, request: null};
       }
       this.mediaSize_ = this.printTicketStore_.mediaSize.getValue();
       this.isLandscapeEnabled_ = this.printTicketStore_.landscape.getValue();
       this.isHeaderFooterEnabled_ =
           this.printTicketStore_.headerFooter.getValue();
       this.colorValue_ = this.printTicketStore_.color.getValue();
       this.isFitToPageEnabled_ = this.printTicketStore_.fitToPage.getValue();
       this.scalingValue_ = this.printTicketStore_.scaling.getValueAsNumber();
       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
       this.marginsType_ = this.printTicketStore_.marginsType.getValue();
       this.isCssBackgroundEnabled_ =
           this.printTicketStore_.cssBackground.getValue();
       this.isSelectionOnlyEnabled_ =
           this.printTicketStore_.selectionOnly.getValue();
       this.selectedDestination_ = this.destinationStore_.selectedDestination;
 
       this.inFlightRequestId_++;
       this.generateDraft_ = this.documentInfo_.isModifiable && previewChanged;
-      this.nativeLayer_.startGetPreview(
-          this.destinationStore_.selectedDestination, this.printTicketStore_,
-          this.documentInfo_, this.generateDraft_, this.inFlightRequestId_);
-      return true;
+      return {
+        id: this.inFlightRequestId_,
+        request: this.nativeLayer_.getPreview(
+            this.destinationStore_.selectedDestination, this.printTicketStore_,
+            this.documentInfo_, this.generateDraft_, this.inFlightRequestId_),
+      };
     },
 
     /** Removes all event listeners that the preview generator has attached. */
     removeEventListeners: function() {
       this.tracker_.removeAll();
     },
 
     /**
      * Adds event listeners to the relevant native layer events.
      * @private
      */
     addEventListeners_: function() {
       var nativeLayerEventTarget = this.nativeLayer_.getEventTarget();
       this.tracker_.add(
           nativeLayerEventTarget,
           print_preview.NativeLayer.EventType.PAGE_LAYOUT_READY,
           this.onPageLayoutReady_.bind(this));
       this.tracker_.add(
           nativeLayerEventTarget,
           print_preview.NativeLayer.EventType.PAGE_COUNT_READY,
           this.onPageCountReady_.bind(this));
       this.tracker_.add(
           nativeLayerEventTarget,
           print_preview.NativeLayer.EventType.PAGE_PREVIEW_READY,
           this.onPagePreviewReady_.bind(this));
-      this.tracker_.add(
-          nativeLayerEventTarget,
-          print_preview.NativeLayer.EventType.PREVIEW_GENERATION_DONE,
-          this.onPreviewGenerationDone_.bind(this));
-      this.tracker_.add(
-          nativeLayerEventTarget,
-          print_preview.NativeLayer.EventType.PREVIEW_GENERATION_FAIL,
-          this.onPreviewGenerationFail_.bind(this));
     },
 
     /**
      * Dispatches a PAGE_READY event to signal that a page preview is ready.
      * @param {number} previewIndex Index of the page with respect to the pages
      *     shown in the preview. E.g an index of 0 is the first displayed page,
      *     but not necessarily the first original document page.
      * @param {number} pageNumber Number of the page with respect to the
      *     document. A value of 3 means it's the third page of the original
      *     document.
@@ skipping 133 matching lines @@
           this.dispatchPreviewStartEvent_(event.previewUid, event.pageIndex);
         }
         this.dispatchPageReadyEvent_(
             previewIndex, pageNumber, event.previewUid);
       }
     },
 
     /**
      * Called when the preview generation is complete. Dispatches a
      * DOCUMENT_READY event.
-     * @param {Event} event Contains the preview UID and response ID.
-     * @private
+     * @param {number} previewResponseId
+     * @param {number} previewUid
      */
-    onPreviewGenerationDone_: function(event) {
-      if (this.inFlightRequestId_ != event.previewResponseId) {
+    onPreviewGenerationDone: function(previewResponseId, previewUid) {
+      if (this.inFlightRequestId_ != previewResponseId) {
         return;  // Ignore old response.
       }
       if (!this.generateDraft_) {
         // Dispatch a PREVIEW_START event since not generating a draft PDF,
         // which includes print preview for non-modifiable documents, does not
         // trigger PAGE_READY events.
-        this.dispatchPreviewStartEvent_(event.previewUid, 0);
+        this.dispatchPreviewStartEvent_(previewUid, 0);
       }
       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.DOCUMENT_READY);
     },
 
     /**
      * Called when the preview generation fails.
      * @private
      */
     onPreviewGenerationFail_: function() {
       // NOTE: No request ID is returned from Chromium so its assumed its the
       // current one.
       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.FAIL);
     }
   };
 
   // Export
   return {PreviewGenerator: PreviewGenerator};
 });