Don't scroll language list to the top when typing PageDown or PageUp

r708735 made the language list scroll to the very top when typing in it,
to avoid the effect of getting momentarily stuck while scrolling up.

However, this prevented users from scrolling with the PageDown or PageUp
keys. So this patch excludes them.

Fixed: 1064190
Change-Id: Iba3a134444ccae7afa31076666e6cbcc3d932c21
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2121255
Reviewed-by: dpapad <dpapad@chromium.org>
Commit-Queue: Oriol Brufau <obrufau@igalia.com>
Cr-Commit-Position: refs/heads/master@{#753432}
diff --git a/chrome/browser/resources/settings/chromeos/os_languages_page/os_add_languages_dialog.js b/chrome/browser/resources/settings/chromeos/os_languages_page/os_add_languages_dialog.js
index b205ec4..db28100 100644
--- a/chrome/browser/resources/settings/chromeos/os_languages_page/os_add_languages_dialog.js
+++ b/chrome/browser/resources/settings/chromeos/os_languages_page/os_add_languages_dialog.js
@@ -166,7 +166,7 @@
     // Close dialog if 'esc' is pressed and the search box is already empty.
     if (e.key == 'Escape' && !this.$.search.getValue().trim()) {
       this.$.dialog.close();
-    } else {
+    } else if (e.key != 'PageDown' && e.key != 'PageUp') {
       this.$.search.scrollIntoViewIfNeeded();
     }
   },
diff --git a/chrome/browser/resources/settings/languages_page/add_languages_dialog.js b/chrome/browser/resources/settings/languages_page/add_languages_dialog.js
index 2a2b607..74e5c3e7 100644
--- a/chrome/browser/resources/settings/languages_page/add_languages_dialog.js
+++ b/chrome/browser/resources/settings/languages_page/add_languages_dialog.js
@@ -166,7 +166,7 @@
     // Close dialog if 'esc' is pressed and the search box is already empty.
     if (e.key == 'Escape' && !this.$.search.getValue().trim()) {
       this.$.dialog.close();
-    } else {
+    } else if (e.key != 'PageDown' && e.key != 'PageUp') {
       this.$.search.scrollIntoViewIfNeeded();
     }
   },