Print Preview: Finish removing global Javascript functions.

chrome/browser/resources/print_preview/preview_generator.js

Index: chrome/browser/resources/print_preview/preview_generator.js
diff --git a/chrome/browser/resources/print_preview/preview_generator.js b/chrome/browser/resources/print_preview/preview_generator.js
index 988033026539d9ccc9eb48de2c2854a44dee283a..330132e03161ce475784d32e729b94804e0ad89e 100644
--- a/chrome/browser/resources/print_preview/preview_generator.js
+++ b/chrome/browser/resources/print_preview/preview_generator.js
@@ -135,15 +135,6 @@ cr.define('print_preview', function() {
      * @private
      */
     this.selectedDestination_ = null;
-
-    /**
-     * Event tracker used to keep track of native layer events.
-     * @type {!EventTracker}
-     * @private
-     */
-    this.tracker_ = new EventTracker();
-
-    this.addEventListeners_();
   }
 
   /**
@@ -170,6 +161,22 @@ cr.define('print_preview', function() {
   PreviewGenerator.prototype = {
     __proto__: cr.EventTarget.prototype,
 
+    /**
+     * Registers the preview generator for the WebUI events it responds to and
+     * adds the listeners to |listenerTracker| so that they can be
+     * automatically removed by this tracker later.
+     * @param {!WebUIListenerTracker} listenerTracker The tracker to add the
+     *     listeners to.
+     */
+    addWebUIEventListeners: function(listenerTracker) {

[dpapad, 2017/07/07 21:12:41]

Not for this CL: Just wondering, would it make sense if we take this approach
one step further and

1) pass the |listenerTracker| in the constructor
2) Call addWebUIEventListeners() within the constructor itself
3) Make addWebUIEventListeners private.

This is similar to what the previous code was doing with EventTracker, except
that it was not injected via the constructor. It also eliminates the misuse of
this API, since calling the public addWebUIEventListeners() could be
accidentally called twice, whereas the constructor can't be called twice.

[rbpotter, 2017/07/07 23:58:39]

I think that would make sense. Will change in follow-up CL.

[rbpotter, 2017/07/08 00:25:39]

Follow up for this and other issues at
https://codereview.chromium.org/2975663003/

+      listenerTracker.add(
+          'page-count-ready', this.onPageCountReady_.bind(this));
+      listenerTracker.add(
+          'page-layout-ready', this.onPageLayoutReady_.bind(this));
+      listenerTracker.add(
+          'page-preview-ready', this.onPagePreviewReady_.bind(this));
+    },
+
     /**
      * Request that new preview be generated. A preview request will not be
      * generated if the print ticket has not changed sufficiently.
@@ -216,31 +223,6 @@ cr.define('print_preview', function() {
       };
     },
 
-    /** 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));
-    },
-
     /**
      * 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
@@ -322,70 +304,86 @@ cr.define('print_preview', function() {
     /**
      * Called when the page layout of the document is ready. Always occurs
      * as a result of a preview request.
-     * @param {Event} event Contains layout info about the document.
+     * @param {{marginTop: number,
+     *          marginLeft: number,
+     *          marginBottom: number,
+     *          marginRight: number,
+     *          contentWidth: number,
+     *          contentHeight: number,
+     *          printableAreaX: number,
+     *          printableAreaY: number,
+     *          printableAreaWidth: number,
+     *          printableAreaHeight: number,
+     *        }} pageLayout Layout information about the document.
+     * @param {boolean} hasCustomPageSizeStyle Whether this document has a
+     *     custom page size or style to use.
      * @private
      */
-    onPageLayoutReady_: function(event) {
+    onPageLayoutReady_: function(pageLayout, hasCustomPageSizeStyle) {
       // NOTE: A request ID is not specified, so assuming its for the current
       // in-flight request.
 
       var origin = new print_preview.Coordinate2d(
-          event.pageLayout.printableAreaX, event.pageLayout.printableAreaY);
+          pageLayout.printableAreaX, pageLayout.printableAreaY);
       var size = new print_preview.Size(
-          event.pageLayout.printableAreaWidth,
-          event.pageLayout.printableAreaHeight);
+          pageLayout.printableAreaWidth, pageLayout.printableAreaHeight);
 
       var margins = new print_preview.Margins(
-          Math.round(event.pageLayout.marginTop),
-          Math.round(event.pageLayout.marginRight),
-          Math.round(event.pageLayout.marginBottom),
-          Math.round(event.pageLayout.marginLeft));
+          Math.round(pageLayout.marginTop), Math.round(pageLayout.marginRight),
+          Math.round(pageLayout.marginBottom),
+          Math.round(pageLayout.marginLeft));
 
       var o = print_preview.ticket_items.CustomMarginsOrientation;
       var pageSize = new print_preview.Size(
-          event.pageLayout.contentWidth + margins.get(o.LEFT) +
-              margins.get(o.RIGHT),
-          event.pageLayout.contentHeight + margins.get(o.TOP) +
+          pageLayout.contentWidth + margins.get(o.LEFT) + margins.get(o.RIGHT),
+          pageLayout.contentHeight + margins.get(o.TOP) +
               margins.get(o.BOTTOM));
 
       this.documentInfo_.updatePageInfo(
           new print_preview.PrintableArea(origin, size), pageSize,
-          event.hasCustomPageSizeStyle, margins);
+          hasCustomPageSizeStyle, margins);
     },
 
     /**
      * Called when the document page count is received from the native layer.
      * Always occurs as a result of a preview request.
-     * @param {Event} event Contains the document's page count.
+     * @param {number} pageCount The document's page count.
+     * @param {number} previewResponseId The request ID that corresponds to this
+     *     page count.
+     * @param {number} fitToPageScaling The scaling required to fit the document
+     *     to page (unused).
      * @private
      */
-    onPageCountReady_: function(event) {
-      if (this.inFlightRequestId_ != event.previewResponseId) {
+    onPageCountReady_: function(
+        pageCount, previewResponseId, fitToPageScaling) {
+      if (this.inFlightRequestId_ != previewResponseId) {
         return;  // Ignore old response.
       }
-      this.documentInfo_.updatePageCount(event.pageCount);
+      this.documentInfo_.updatePageCount(pageCount);
       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
     },
 
     /**
      * Called when a page's preview has been generated. Dispatches a
      * PAGE_READY event.
-     * @param {Event} event Contains the page index and preview UID.
+     * @param {number} pageIndex The index of the page whose preview is ready.
+     * @param {number} previewUid The unique ID of the print preview UI.
+     * @param {number} previewResponseId The preview request ID that this page
+     *     preview is a response to.
      * @private
      */
-    onPagePreviewReady_: function(event) {
-      if (this.inFlightRequestId_ != event.previewResponseId) {
+    onPagePreviewReady_: function(pageIndex, previewUid, previewResponseId) {
+      if (this.inFlightRequestId_ != previewResponseId) {
         return;  // Ignore old response.
       }
-      var pageNumber = event.pageIndex + 1;
+      var pageNumber = pageIndex + 1;
       var pageNumberSet = this.printTicketStore_.pageRange.getPageNumberSet();
       if (pageNumberSet.hasPageNumber(pageNumber)) {
         var previewIndex = pageNumberSet.getPageNumberIndex(pageNumber);
         if (previewIndex == 0) {
-          this.dispatchPreviewStartEvent_(event.previewUid, event.pageIndex);
+          this.dispatchPreviewStartEvent_(previewUid, pageIndex);
         }
-        this.dispatchPageReadyEvent_(
-            previewIndex, pageNumber, event.previewUid);
+        this.dispatchPageReadyEvent_(previewIndex, pageNumber, previewUid);
       }
     },