Use `createPromiseCapability` in `/web` files

In various viewer files, there's a number of cases where we basically duplicate the functionality of `createPromiseCapability` manually.
As far as I can tell, a couple of these cases have existed for a very long time, and notable even before the `createPromiseCapability` utility function existed.

Also, since we can write ES6 code now, the patch also replaces a couple of `bind` usages with arrow functions in code that's touched in the patch.

.eslintrc

@@ -138,7 +138,7 @@
     }],
 
     // ECMAScript 6
-    "arrow-body-style": ["error", "as-needed"],
+    "arrow-body-style": ["error", "always"],
     "arrow-parens": ["error", "always"],
     "arrow-spacing": ["error", {
       "before": true,

web/pdf_document_properties.js

@@ -14,6 +14,7 @@
  */
 
 import { getPDFFileNameFromURL, mozL10n } from './ui_utils';
+import { createPromiseCapability } from './pdfjs';
 import { OverlayManager } from './overlay_manager';
 
 /**
@@ -44,10 +45,7 @@ var PDFDocumentProperties = (function PDFDocumentPropertiesClosure() {
     if (options.closeButton) {
       options.closeButton.addEventListener('click', this.close.bind(this));
     }
-
-    this.dataAvailablePromise = new Promise(function (resolve) {
-      this.resolveDataAvailable = resolve;
-    }.bind(this));
+    this._dataAvailableCapability = createPromiseCapability();
 
     OverlayManager.register(this.overlayName, this.container,
                             this.close.bind(this));
@@ -59,9 +57,9 @@ var PDFDocumentProperties = (function PDFDocumentPropertiesClosure() {
      */
     open: function PDFDocumentProperties_open() {
       Promise.all([OverlayManager.open(this.overlayName),
-                   this.dataAvailablePromise]).then(function () {
+                   this._dataAvailableCapability.promise]).then(() => {
         this._getProperties();
-      }.bind(this));
+      });
     },
 
     /**
@@ -97,7 +95,7 @@ var PDFDocumentProperties = (function PDFDocumentPropertiesClosure() {
         function PDFDocumentProperties_setDocumentAndUrl(pdfDocument, url) {
       this.pdfDocument = pdfDocument;
       this.url = url;
-      this.resolveDataAvailable();
+      this._dataAvailableCapability.resolve();
     },
 
     /**
@@ -110,16 +108,16 @@ var PDFDocumentProperties = (function PDFDocumentPropertiesClosure() {
         return;
       }
       // Get the file size (if it hasn't already been set).
-      this.pdfDocument.getDownloadInfo().then(function(data) {
+      this.pdfDocument.getDownloadInfo().then((data) => {
         if (data.length === this.rawFileSize) {
           return;
         }
         this.setFileSize(data.length);
         this._updateUI(this.fields['fileSize'], this._parseFileSize());
-      }.bind(this));
+      });
 
       // Get the document properties.
-      this.pdfDocument.getMetadata().then(function(data) {
+      this.pdfDocument.getMetadata().then((data) => {
         var content = {
           'fileName': getPDFFileNameFromURL(this.url),
           'fileSize': this._parseFileSize(),
@@ -139,7 +137,7 @@ var PDFDocumentProperties = (function PDFDocumentPropertiesClosure() {
         for (var identifier in content) {
           this._updateUI(this.fields[identifier], content[identifier]);
         }
-      }.bind(this));
+      });
     },
 
     /**

web/pdf_find_controller.js

@@ -81,9 +81,9 @@ var PDFFindController = (function PDFFindControllerClosure() {
       this.dirtyMatch = false;
       this.findTimeout = null;
 
-      this.firstPagePromise = new Promise(function (resolve) {
+      this._firstPagePromise = new Promise((resolve) => {
         this.resolveFirstPage = resolve;
-      }.bind(this));
+      });
     },
 
     normalize: function PDFFindController_normalize(text) {
@@ -277,7 +277,7 @@ var PDFFindController = (function PDFFindControllerClosure() {
       this.state = state;
       this.updateUIState(FindStates.FIND_PENDING);
 
-      this.firstPagePromise.then(function() {
+      this._firstPagePromise.then(function() {
         this.extractText();
 
         clearTimeout(this.findTimeout);

web/pdf_page_view.js

@@ -18,7 +18,8 @@ import {
   roundToDivide
 } from './ui_utils';
 import {
-  CustomStyle, PDFJS, RenderingCancelledException, SVGGraphics
+  createPromiseCapability, CustomStyle, PDFJS, RenderingCancelledException,
+  SVGGraphics
 } from './pdfjs';
 import { domEvents } from './dom_events';
 import { RenderingStates } from './pdf_rendering_queue';
@@ -493,14 +494,10 @@ var PDFPageView = (function PDFPageViewClosure() {
     },
 
     paintOnCanvas: function (canvasWrapper) {
-      var resolveRenderPromise, rejectRenderPromise;
-      var promise = new Promise(function (resolve, reject) {
-        resolveRenderPromise = resolve;
-        rejectRenderPromise = reject;
-      });
+      var renderCapability = createPromiseCapability();
 
       var result = {
-        promise: promise,
+        promise: renderCapability.promise,
         onRenderContinue: function (cont) {
           cont();
         },
@@ -589,11 +586,11 @@ var PDFPageView = (function PDFPageViewClosure() {
       renderTask.promise.then(
         function pdfPageRenderCallback() {
           showCanvas();
-          resolveRenderPromise(undefined);
+          renderCapability.resolve(undefined);
         },
         function pdfPageRenderError(error) {
           showCanvas();
-          rejectRenderPromise(error);
+          renderCapability.reject(error);
         }
       );
 

web/pdf_thumbnail_view.js

@@ -13,8 +13,8 @@
  * limitations under the License.
  */
 
+import { createPromiseCapability, RenderingCancelledException } from './pdfjs';
 import { getOutputScale, mozL10n } from './ui_utils';
-import { RenderingCancelledException } from './pdfjs';
 import { RenderingStates } from './pdf_rendering_queue';
 
 var THUMBNAIL_WIDTH = 98; // px
@@ -275,11 +275,7 @@ var PDFThumbnailView = (function PDFThumbnailViewClosure() {
 
       this.renderingState = RenderingStates.RUNNING;
 
-      var resolveRenderPromise, rejectRenderPromise;
-      var promise = new Promise(function (resolve, reject) {
-        resolveRenderPromise = resolve;
-        rejectRenderPromise = reject;
-      });
+      var renderCapability = createPromiseCapability();
 
       var self = this;
       function thumbnailDrawCallback(error) {
@@ -293,7 +289,7 @@ var PDFThumbnailView = (function PDFThumbnailViewClosure() {
         if (((typeof PDFJSDev === 'undefined' ||
               !PDFJSDev.test('PDFJS_NEXT')) && error === 'cancelled') ||
             error instanceof RenderingCancelledException) {
-          resolveRenderPromise(undefined);
+          renderCapability.resolve(undefined);
           return;
         }
 
@@ -301,9 +297,9 @@ var PDFThumbnailView = (function PDFThumbnailViewClosure() {
         self._convertCanvasToImage();
 
         if (!error) {
-          resolveRenderPromise(undefined);
+          renderCapability.resolve(undefined);
         } else {
-          rejectRenderPromise(error);
+          renderCapability.reject(error);
         }
       }
 
@@ -336,7 +332,7 @@ var PDFThumbnailView = (function PDFThumbnailViewClosure() {
           thumbnailDrawCallback(error);
         }
       );
-      return promise;
+      return renderCapability.promise;
     },
 
     setImage: function PDFThumbnailView_setImage(pageView) {

web/pdf_viewer.js

@@ -13,17 +13,15 @@
  * limitations under the License.
  */
 
+import { createPromiseCapability, PDFJS } from './pdfjs';
 import {
   CSS_UNITS, DEFAULT_SCALE, DEFAULT_SCALE_VALUE, getVisibleElements,
   MAX_AUTO_SCALE, RendererType, SCROLLBAR_PADDING, scrollIntoView,
   UNKNOWN_SCALE, VERTICAL_PADDING, watchScroll
 } from './ui_utils';
-import {
-  PDFRenderingQueue, RenderingStates,
-} from './pdf_rendering_queue';
+import { PDFRenderingQueue, RenderingStates } from './pdf_rendering_queue';
 import { AnnotationLayerBuilder } from './annotation_layer_builder';
 import { domEvents } from './dom_events';
-import { PDFJS } from './pdfjs';
 import { PDFPageView } from './pdf_page_view';
 import { SimpleLinkService } from './pdf_link_service';
 import { TextLayerBuilder } from './text_layer_builder';
@@ -313,41 +311,34 @@ var PDFViewer = (function pdfViewer() {
       if (!pdfDocument) {
         return;
       }
-
       var pagesCount = pdfDocument.numPages;
-      var self = this;
 
-      var resolvePagesPromise;
-      var pagesPromise = new Promise(function (resolve) {
-        resolvePagesPromise = resolve;
-      });
-      this.pagesPromise = pagesPromise;
-      pagesPromise.then(function () {
-        self._pageViewsReady = true;
-        self.eventBus.dispatch('pagesloaded', {
-          source: self,
-          pagesCount: pagesCount
+      var pagesCapability = createPromiseCapability();
+      this.pagesPromise = pagesCapability.promise;
+
+      pagesCapability.promise.then(() => {
+        this._pageViewsReady = true;
+        this.eventBus.dispatch('pagesloaded', {
+          source: this,
+          pagesCount,
         });
       });
 
       var isOnePageRenderedResolved = false;
-      var resolveOnePageRendered = null;
-      var onePageRendered = new Promise(function (resolve) {
-        resolveOnePageRendered = resolve;
-      });
-      this.onePageRendered = onePageRendered;
+      var onePageRenderedCapability = createPromiseCapability();
+      this.onePageRendered = onePageRenderedCapability.promise;
 
-      var bindOnAfterAndBeforeDraw = function (pageView) {
-        pageView.onBeforeDraw = function pdfViewLoadOnBeforeDraw() {
+      var bindOnAfterAndBeforeDraw = (pageView) => {
+        pageView.onBeforeDraw = () => {
           // Add the page to the buffer at the start of drawing. That way it can
           // be evicted from the buffer and destroyed even if we pause its
           // rendering.
-          self._buffer.push(this);
+          this._buffer.push(pageView);
         };
-        pageView.onAfterDraw = function pdfViewLoadOnAfterDraw() {
+        pageView.onAfterDraw = () => {
           if (!isOnePageRenderedResolved) {
             isOnePageRenderedResolved = true;
-            resolveOnePageRendered();
+            onePageRenderedCapability.resolve();
           }
         };
       };
@@ -357,7 +348,7 @@ var PDFViewer = (function pdfViewer() {
 
       // Fetch a single page so we can get a viewport that will be the default
       // viewport for all pages
-      return firstPagePromise.then(function(pdfPage) {
+      return firstPagePromise.then((pdfPage) => {
         var scale = this.currentScale;
         var viewport = pdfPage.getViewport(scale * CSS_UNITS);
         for (var pageNum = 1; pageNum <= pagesCount; ++pageNum) {
@@ -382,34 +373,31 @@ var PDFViewer = (function pdfViewer() {
           this._pages.push(pageView);
         }
 
-        var linkService = this.linkService;
-
         // Fetch all the pages since the viewport is needed before printing
         // starts to create the correct size canvas. Wait until one page is
         // rendered so we don't tie up too many resources early on.
-        onePageRendered.then(function () {
-          if (!PDFJS.disableAutoFetch) {
-            var getPagesLeft = pagesCount;
-            for (var pageNum = 1; pageNum <= pagesCount; ++pageNum) {
-              pdfDocument.getPage(pageNum).then(function (pageNum, pdfPage) {
-                var pageView = self._pages[pageNum - 1];
-                if (!pageView.pdfPage) {
-                  pageView.setPdfPage(pdfPage);
-                }
-                linkService.cachePageRef(pageNum, pdfPage.ref);
-                getPagesLeft--;
-                if (!getPagesLeft) {
-                  resolvePagesPromise();
-                }
-              }.bind(null, pageNum));
-            }
-          } else {
+        onePageRenderedCapability.promise.then(() => {
+          if (PDFJS.disableAutoFetch) {
             // XXX: Printing is semi-broken with auto fetch disabled.
-            resolvePagesPromise();
+            pagesCapability.resolve();
+            return;
+          }
+          var getPagesLeft = pagesCount;
+          for (var pageNum = 1; pageNum <= pagesCount; ++pageNum) {
+            pdfDocument.getPage(pageNum).then(function(pageNum, pdfPage) {
+              var pageView = this._pages[pageNum - 1];
+              if (!pageView.pdfPage) {
+                pageView.setPdfPage(pdfPage);
+              }
+              this.linkService.cachePageRef(pageNum, pdfPage.ref);
+              if (--getPagesLeft === 0) {
+                pagesCapability.resolve();
+              }
+            }.bind(this, pageNum));
           }
         });
 
-        self.eventBus.dispatch('pagesinit', {source: self});
+        this.eventBus.dispatch('pagesinit', { source: this });
 
         if (this.defaultRenderingQueue) {
           this.update();
@@ -418,7 +406,7 @@ var PDFViewer = (function pdfViewer() {
         if (this.findController) {
           this.findController.resolveFirstPage();
         }
-      }.bind(this));
+      });
     },
 
     /**