Remove the disableCreateObjectURL option from web/app_options.js

Prior to PR 11601, the `disableCreateObjectURL` option was present on `getDocument` in the API, since it was (potentially) used when decoding JPEG images natively in the browser. Hence setting this option, which was done automatically using compatibility-code, were in some browsers necessary in order for e.g. JPEG images to be correctly rendered.

The downside of the `disableCreateObjectURL` option is that memory usage increases significantly, since we're forced to build and use `data:` URIs (rather than `blob:` URLs).
However, at this point in time the `disableCreateObjectURL` option is only necessary for *some* (non-essential) functionality in the default viewer; in particular:
 - The openfile functionality, used only when manually opening a new file in the default viewer.
 - The download functionality, used when downloading either the PDF document itself or its attached files (if such exists).
 - The print functionality, in the generic `PDFPrintService` implementation.

Hence neither the general PDF.js library, nor the *basic* functionality of the default viewer, depends on the `disableCreateObjectURL` option any more; which is why I'm thus proposing that we remove the option since using it is a performance footgun.

*Please note:* To not outright break currently "supported" browsers, which lack proper `URL.createObjectURL` support, this patch purposely keeps the compatibility-code to explicitly disable `URL.createObjectURL` usage *only* for browsers which are known to not work correctly.[1]

While it's certainly possible that there's additional, likely older, browsers with broken `URL.createObjectURL` support, the last time that these types of problems were reported was over *three* years ago.[2]
Hence in the *very* unlikely event that additional problems occur, as a result of these changes, we can either add a new case in the compatibility-code or simply declare the affected browser as unsupported.

---
[1] Which are IE11 (see issue 3977), and Google Chrome on iOS (see PR 8081).

[2] Given that `URL.createObjectURL` is used by default, you'd really expect more reports if these problems were widespread.

web/app.js

@@ -72,6 +72,7 @@ import { PDFThumbnailViewer } from "./pdf_thumbnail_viewer.js";
 import { PDFViewer } from "./pdf_viewer.js";
 import { SecondaryToolbar } from "./secondary_toolbar.js";
 import { Toolbar } from "./toolbar.js";
+import { viewerCompatibilityParams } from "./viewer_compatibility.js";
 import { ViewHistory } from "./view_history.js";
 
 const DEFAULT_SCALE_DELTA = 1.1;
@@ -408,9 +409,7 @@ const PDFViewerApplication = {
     });
     this.pdfLinkService = pdfLinkService;
 
-    const downloadManager = this.externalServices.createDownloadManager({
-      disableCreateObjectURL: AppOptions.get("disableCreateObjectURL"),
-    });
+    const downloadManager = this.externalServices.createDownloadManager();
     this.downloadManager = downloadManager;
 
     const findController = new PDFFindController({
@@ -2225,7 +2224,7 @@ if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
     }
     const file = evt.fileInput.files[0];
 
-    if (!AppOptions.get("disableCreateObjectURL")) {
+    if (!viewerCompatibilityParams.disableCreateObjectURL) {
       let url = URL.createObjectURL(file);
       if (file.name) {
         url = { url, originalUrl: file.name };

web/app_options.js

@@ -42,12 +42,6 @@ const defaultOptions = {
     value: "",
     kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
   },
-  disableCreateObjectURL: {
-    /** @type {boolean} */
-    value: false,
-    compatibility: viewerCompatibilityParams.disableCreateObjectURL,
-    kind: OptionKind.VIEWER,
-  },
   disableHistory: {
     /** @type {boolean} */
     value: false,

web/download_manager.js

@@ -23,9 +23,6 @@ if (typeof PDFJSDev !== "undefined" && !PDFJSDev.test("CHROME || GENERIC")) {
   );
 }
 
-const DISABLE_CREATE_OBJECT_URL =
-  viewerCompatibilityParams.disableCreateObjectURL || false;
-
 function download(blobUrl, filename) {
   const a = document.createElement("a");
   if (!a.click) {
@@ -46,10 +43,6 @@ function download(blobUrl, filename) {
 }
 
 class DownloadManager {
-  constructor({ disableCreateObjectURL = DISABLE_CREATE_OBJECT_URL }) {
-    this.disableCreateObjectURL = disableCreateObjectURL;
-  }
-
   downloadUrl(url, filename) {
     if (!createValidAbsoluteUrl(url, "http://example.com")) {
       return; // restricted/invalid URL
@@ -66,7 +59,7 @@ class DownloadManager {
     const blobUrl = createObjectURL(
       data,
       contentType,
-      this.disableCreateObjectURL
+      viewerCompatibilityParams.disableCreateObjectURL
     );
     download(blobUrl, filename);
   }
@@ -80,7 +73,7 @@ class DownloadManager {
       return;
     }
 
-    if (this.disableCreateObjectURL) {
+    if (viewerCompatibilityParams.disableCreateObjectURL) {
       // URL.createObjectURL is not supported
       this.downloadUrl(url, filename);
       return;

web/firefoxcom.js

@@ -88,10 +88,6 @@ const FirefoxCom = (function FirefoxComClosure() {
 })();
 
 class DownloadManager {
-  constructor(options) {
-    this.disableCreateObjectURL = false;
-  }
-
   downloadUrl(url, filename) {
     FirefoxCom.request("download", {
       originalUrl: url,

web/pdf_attachment_viewer.js

@@ -15,6 +15,7 @@
 
 import { createPromiseCapability, getFilenameFromUrl } from "pdfjs-lib";
 import { BaseTreeViewer } from "./base_tree_viewer.js";
+import { viewerCompatibilityParams } from "./viewer_compatibility.js";
 
 /**
  * @typedef {Object} PDFAttachmentViewerOptions
@@ -169,7 +170,7 @@ class PDFAttachmentViewer extends BaseTreeViewer {
       const element = document.createElement("a");
       if (
         /\.pdf$/i.test(filename) &&
-        !this.downloadManager.disableCreateObjectURL
+        !viewerCompatibilityParams.disableCreateObjectURL
       ) {
         this._bindPdfLink(element, { content: item.content, filename });
       } else {

web/pdf_print_service.js

@@ -15,7 +15,7 @@
 
 import { CSS_UNITS, NullL10n } from "./ui_utils.js";
 import { PDFPrintServiceFactory, PDFViewerApplication } from "./app.js";
-import { AppOptions } from "./app_options.js";
+import { viewerCompatibilityParams } from "./viewer_compatibility.js";
 
 let activeService = null;
 let overlayManager = null;
@@ -78,7 +78,6 @@ function PDFPrintService(
   this.printContainer = printContainer;
   this._printResolution = printResolution || 150;
   this.l10n = l10n || NullL10n;
-  this.disableCreateObjectURL = AppOptions.get("disableCreateObjectURL");
   this.currentPage = -1;
   // The temporary canvas where renderPage paints one page at a time.
   this.scratchCanvas = document.createElement("canvas");
@@ -188,7 +187,10 @@ PDFPrintService.prototype = {
     img.style.height = printItem.height;
 
     const scratchCanvas = this.scratchCanvas;
-    if ("toBlob" in scratchCanvas && !this.disableCreateObjectURL) {
+    if (
+      "toBlob" in scratchCanvas &&
+      !viewerCompatibilityParams.disableCreateObjectURL
+    ) {
       scratchCanvas.toBlob(function (blob) {
         img.src = URL.createObjectURL(blob);
       });