Remove the Uint8Array.prototype.toHex(), Uint8Array.prototype.toBase64(), and Uint8Array.fromBase64() polyfills

(During rebasing of the previous patches I happened to look at the polyfills and noticed that this one could be removed now.)

See:
 - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/toHex#browser_compatibility
 - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/toBase64#browser_compatibility
 - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/fromBase64#browser_compatibility

Note that technically this functionality can still be disabled via a preference in Firefox, however that's slated for removal in [bug 1985120](https://bugzilla.mozilla.org/show_bug.cgi?id=1985120).
Looking at the Firefox source-code, see https://searchfox.org/firefox-main/search?q=array.tobase64%28%29&path=&case=false&regexp=false, you can see that it's already being used *unconditionally* elsewhere in the browser hence removing the polyfills ought to be fine (since toggling the preference would break other parts of the browser).

Author: Snuffleupagus

src/core/document.js

@@ -27,7 +27,6 @@ import {
   stringToBytes,
   stringToPDFString,
   stringToUTF8String,
-  toHexUtil,
   unreachable,
   Util,
   warn,
@@ -1605,8 +1604,8 @@ class PDFDocument {
     }
 
     return shadow(this, "fingerprints", [
-      toHexUtil(hashOriginal),
-      hashModified ? toHexUtil(hashModified) : null,
+      hashOriginal.toHex(),
+      hashModified?.toHex() ?? null,
     ]);
   }
 

src/core/xfa/template.js

@@ -90,7 +90,6 @@ import {
   XFAObject,
   XFAObjectArray,
 } from "./xfa_object.js";
-import { fromBase64Util, Util, warn } from "../../shared/util.js";
 import {
   getBBox,
   getColor,
@@ -103,6 +102,7 @@ import {
   getStringOption,
   HTMLResult,
 } from "./utils.js";
+import { Util, warn } from "../../shared/util.js";
 import { getMetrics } from "./fonts.js";
 import { recoverJsURL } from "../core_utils.js";
 import { searchNode } from "./som.js";
@@ -3420,7 +3420,7 @@ class Image extends StringObject {
     }
 
     if (!buffer && this.transferEncoding === "base64") {
-      buffer = fromBase64Util(this[$content]);
+      buffer = Uint8Array.fromBase64(this[$content]);
     }
 
     if (!buffer) {

src/display/editor/drawers/signaturedraw.js

@@ -13,10 +13,10 @@
  * limitations under the License.
  */
 
-import { fromBase64Util, toBase64Util, warn } from "../../../shared/util.js";
 import { ContourDrawOutline } from "./contour.js";
 import { InkDrawOutline } from "./inkdraw.js";
 import { Outline } from "./outline.js";
+import { warn } from "../../../shared/util.js";
 
 const BASE_HEADER_LENGTH = 8;
 const POINTS_PROPERTIES_NUMBER = 3;
@@ -749,12 +749,12 @@ class SignatureExtractor {
     const buf = await new Response(cs.readable).arrayBuffer();
     const bytes = new Uint8Array(buf);
 
-    return toBase64Util(bytes);
+    return bytes.toBase64();
   }
 
   static async decompressSignature(signatureData) {
     try {
-      const bytes = fromBase64Util(signatureData);
+      const bytes = Uint8Array.fromBase64(signatureData);
       const { readable, writable } = new DecompressionStream("deflate-raw");
       const writer = writable.getWriter();
       await writer.ready;

src/display/font_loader.js

@@ -19,7 +19,6 @@ import {
   isNodeJS,
   shadow,
   string32,
-  toBase64Util,
   unreachable,
   warn,
 } from "../shared/util.js";
@@ -408,7 +407,7 @@ class FontFaceObject {
       return null;
     }
     // Add the @font-face rule to the document.
-    const url = `url(data:${this.mimetype};base64,${toBase64Util(this.data)});`;
+    const url = `url(data:${this.mimetype};base64,${this.data.toBase64()});`;
     let rule;
     if (!this.cssFontInfo) {
       rule = `@font-face {font-family:"${this.loadedName}";src:${url}}`;

src/shared/util.js

@@ -1235,31 +1235,6 @@ function MathClamp(v, min, max) {
   return Math.min(Math.max(v, min), max);
 }
 
-// TODO: Remove this once `Uint8Array.prototype.toHex` is generally available.
-function toHexUtil(arr) {
-  if (Uint8Array.prototype.toHex) {
-    return arr.toHex();
-  }
-  return Array.from(arr, num => hexNumbers[num]).join("");
-}
-
-// TODO: Remove this once `Uint8Array.prototype.toBase64` is generally
-//       available.
-function toBase64Util(arr) {
-  if (Uint8Array.prototype.toBase64) {
-    return arr.toBase64();
-  }
-  return btoa(bytesToString(arr));
-}
-
-// TODO: Remove this once `Uint8Array.fromBase64` is generally available.
-function fromBase64Util(str) {
-  if (Uint8Array.fromBase64) {
-    return Uint8Array.fromBase64(str);
-  }
-  return stringToBytes(atob(str));
-}
-
 // TODO: Remove this once the `javascript.options.experimental.math_sumprecise`
 //       preference is removed from Firefox.
 if (typeof Math.sumPrecise !== "function") {
@@ -1325,7 +1300,6 @@ export {
   FeatureTest,
   FONT_IDENTITY_MATRIX,
   FormatError,
-  fromBase64Util,
   getModificationDate,
   getUuid,
   getVerbosityLevel,
@@ -1355,8 +1329,6 @@ export {
   stringToPDFString,
   stringToUTF8String,
   TextRenderingMode,
-  toBase64Util,
-  toHexUtil,
   UnknownErrorException,
   unreachable,
   updateUrlHash,

test/font/font_core_spec.js

@@ -14,22 +14,10 @@
  * limitations under the License.
  */
 
-import { bytesToString, stringToBytes } from "../../src/shared/util.js";
-
-function decodeFontData(base64) {
-  const str = atob(base64);
-  return stringToBytes(str);
-}
-
-function encodeFontData(data) {
-  const str = bytesToString(data);
-  return btoa(str);
-}
-
 async function ttx(data) {
   const response = await fetch("/ttx", {
     method: "POST",
-    body: encodeFontData(data),
+    body: data.toBase64(),
   });
 
   if (!response.ok) {
@@ -45,4 +33,4 @@ function verifyTtxOutput(output) {
   }
 }
 
-export { decodeFontData, encodeFontData, ttx, verifyTtxOutput };
+export { ttx, verifyTtxOutput };