From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Shelley Vohr <shelley.vohr@gmail.com>
Date: Mon, 17 Jan 2022 23:47:54 +0100
Subject: fix: crash when saving edited PDF files

This commit fixes a crash that persists any time a user attempts to
download an edited PDF. This was happening because the logic flow for
downloading of any edited PDF triggers a call to
chrome.fileSystem.chooseEntry, which we do not support and which
therefore causes unmapped page access crashes.

This patch can be removed should we choose to support chrome.fileSystem
or support it enough to fix the crash.

diff --git a/chrome/browser/resources/pdf/pdf_viewer.js b/chrome/browser/resources/pdf/pdf_viewer.js
index f3d71309080248024983891acb17d4df69648056..3cd563ed13ab9bd8fa084f54eb8f112b66399eb9 100644
--- a/chrome/browser/resources/pdf/pdf_viewer.js
+++ b/chrome/browser/resources/pdf/pdf_viewer.js
@@ -966,25 +966,12 @@ export class PDFViewerElement extends PDFViewerBaseElement {
       dataArray = [result.dataToSave];
     }
 
+    const a = document.createElement('a');
+    a.download = this.attachments_[index].name;
     const blob = new Blob(dataArray);
-    const fileName = this.attachments_[index].name;
-    chrome.fileSystem.chooseEntry(
-        {type: 'saveFile', suggestedName: fileName}, entry => {
-          if (chrome.runtime.lastError) {
-            if (chrome.runtime.lastError.message !== 'User cancelled') {
-              console.error(
-                  'chrome.fileSystem.chooseEntry failed: ' +
-                  chrome.runtime.lastError.message);
-            }
-            return;
-          }
-          entry.createWriter(writer => {
-            writer.write(blob);
-            // Unblock closing the window now that the user has saved
-            // successfully.
-            chrome.mimeHandlerPrivate.setShowBeforeUnloadDialog(false);
-          });
-        });
+    a.href = URL.createObjectURL(blob);
+    a.click();
+    URL.revokeObjectURL(a.href);
   }
 
   /**
@@ -1111,30 +1098,13 @@ export class PDFViewerElement extends PDFViewerBaseElement {
     if (!fileName.toLowerCase().endsWith('.pdf')) {
       fileName = fileName + '.pdf';
     }
-    // Create blob before callback to avoid race condition.
+
+    const a = document.createElement('a');
+    a.download = fileName;
     const blob = new Blob([result.dataToSave], {type: 'application/pdf'});
-    chrome.fileSystem.chooseEntry(
-        {
-          type: 'saveFile',
-          accepts: [{description: '*.pdf', extensions: ['pdf']}],
-          suggestedName: fileName
-        },
-        entry => {
-          if (chrome.runtime.lastError) {
-            if (chrome.runtime.lastError.message !== 'User cancelled') {
-              console.error(
-                  'chrome.fileSystem.chooseEntry failed: ' +
-                  chrome.runtime.lastError.message);
-            }
-            return;
-          }
-          entry.createWriter(writer => {
-            writer.write(blob);
-            // Unblock closing the window now that the user has saved
-            // successfully.
-            chrome.mimeHandlerPrivate.setShowBeforeUnloadDialog(false);
-          });
-        });
+    a.href = URL.createObjectURL(blob);
+    a.click();
+    URL.revokeObjectURL(a.href);
 
     // <if expr="enable_ink">
     // Saving in Annotation mode is destructive: crbug.com/919364
