Convert FirefoxPrintService and PDFPrintService into standard classes

Note that both of the affected files are old enough to predate the general availability of `class`.

web/firefox_print_service.js

@@ -114,7 +114,8 @@ function composePage(
   };
 }
 
-function FirefoxPrintService(
+class FirefoxPrintService {
+  constructor(
     pdfDocument,
     pagesOverview,
     printContainer,
@@ -132,7 +133,6 @@ function FirefoxPrintService(
       printAnnotationStoragePromise || Promise.resolve();
   }
 
-FirefoxPrintService.prototype = {
   layout() {
     const {
       pdfDocument,
@@ -179,7 +179,7 @@ FirefoxPrintService.prototype = {
         _printAnnotationStoragePromise
       );
     }
-  },
+  }
 
   destroy() {
     this.printContainer.textContent = "";
@@ -191,8 +191,8 @@ FirefoxPrintService.prototype = {
       this.pageStyleSheet.remove();
       this.pageStyleSheet = null;
     }
-  },
-};
+  }
+}
 
 PDFPrintServiceFactory.instance = {
   get supportsPrinting() {

web/pdf_print_service.js

@@ -62,7 +62,8 @@ function renderPage(
   });
 }
 
-function PDFPrintService(
+class PDFPrintService {
+  constructor(
     pdfDocument,
     pagesOverview,
     printContainer,
@@ -85,7 +86,6 @@ function PDFPrintService(
     this.scratchCanvas = document.createElement("canvas");
   }
 
-PDFPrintService.prototype = {
   layout() {
     this.throwIfInactive();
 
@@ -114,7 +114,7 @@ PDFPrintService.prototype = {
     this.pageStyleSheet = document.createElement("style");
     this.pageStyleSheet.textContent = `@page { size: ${width}pt ${height}pt;}`;
     body.append(this.pageStyleSheet);
-  },
+  }
 
   destroy() {
     if (activeService !== this) {
@@ -139,7 +139,7 @@ PDFPrintService.prototype = {
         overlayManager.close(dialog);
       }
     });
-  },
+  }
 
   renderPages() {
     if (this.pdfDocument.isPureXfa) {
@@ -172,7 +172,7 @@ PDFPrintService.prototype = {
         }, reject);
     };
     return new Promise(renderNextPage);
-  },
+  }
 
   useRenderedPage() {
     this.throwIfInactive();
@@ -195,7 +195,7 @@ PDFPrintService.prototype = {
       img.onload = resolve;
       img.onerror = reject;
     });
-  },
+  }
 
   performPrint() {
     this.throwIfInactive();
@@ -213,18 +213,18 @@ PDFPrintService.prototype = {
         setTimeout(resolve, 20); // Tidy-up.
       }, 0);
     });
-  },
+  }
 
   get active() {
     return this === activeService;
-  },
+  }
 
   throwIfInactive() {
     if (!this.active) {
       throw new Error("This print request was cancelled or completed.");
     }
-  },
-};
+  }
+}
 
 const print = window.print;
 window.print = function () {