Allow PageInfoBubble to be accessed with up and down arrows.

Bug: 857118
Change-Id: Icc6c20824c5ff558e778768aec24a439002f9f6c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1582519Reviewed-by: Ben Wells <benwells@chromium.org>
Commit-Queue: Charlene Yan <cyan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659512}

chrome/browser/ui/views/page_info/page_info_bubble_view.cc

@@ -476,6 +476,8 @@ PageInfoBubbleView::PageInfoBubbleView(
   const int side_margin = margins().left();
   DCHECK_EQ(margins().left(), margins().right());
 
+  EnableUpDownKeyboardAccelerators();
+
   ChromeLayoutProvider* layout_provider = ChromeLayoutProvider::Get();
 
   // In Harmony, the last view is a HoverButton, which overrides the bottom