Bookmarks: Fix and re-enable BookmarksExtensionAPITest.All

Failure could not be reproduced locally on a Chrome OS debug build;
this is a speculative fix based on the stack trace.

Bug: 1028272
Change-Id: I1c10839a82061b6ce4daf7a1d8d80ce0e6210dbe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935720Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719242}

chrome/test/data/webui/bookmarks/bookmarks_browsertest.js

@@ -223,7 +223,7 @@ var BookmarksExtensionAPITest = class extends BookmarksBrowserTest {
   }
 };
 
-TEST_F('BookmarksExtensionAPITest', 'DISABLED_All', function() {
+TEST_F('BookmarksExtensionAPITest', 'All', function() {
   mocha.run();
 });
 

chrome/test/data/webui/bookmarks/extension_api_test.js

@@ -209,7 +209,8 @@ test('bookmarkManagerPrivate', async () => {
             assertEquals(count, result.length);
 
             // Look for barNode's index.
-            for (let barIndex = 0; barIndex < result.length; barIndex++) {
+            let barIndex;
+            for (barIndex = 0; barIndex < result.length; barIndex++) {
               if (result[barIndex].id == barNode.id) {
                 break;
               }
@@ -251,7 +252,8 @@ test('bookmarkManagerPrivate', async () => {
             assertEquals(count, result.length);
 
             // Look for fooNode2's index.
-            for (let foo2Index = 0; foo2Index < result.length; foo2Index++) {
+            let foo2Index;
+            for (foo2Index = 0; foo2Index < result.length; foo2Index++) {
               if (result[foo2Index].id == fooNode2.id) {
                 break;
               }