Prevent quick answers menu from moving while menu is being populated.

Previously the Quick Answers view was added first to the context menu,
causing it to jump as items were added/removed to the menu.

Bug: b/173569669
Test: Manually deployed and verified we no longer get multiple |OnBoundariesChanged| events.
Change-Id: I6b8e52b7e24f653dcf033eb218c26b61f4de86e4
Cq-Include-Trybots: luci.chrome.try:linux-chromeos-chrome
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567183Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Yue Li <updowndota@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Auto-Submit: Jeroen Dhollander <jeroendh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833843}

chrome/browser/renderer_context_menu/render_view_context_menu.cc

@@ -794,8 +794,6 @@ void RenderViewContextMenu::WriteURLToClipboard(const GURL& url) {
 void RenderViewContextMenu::InitMenu() {
   RenderViewContextMenuBase::InitMenu();
 
-  AppendQuickAnswersItems();
-
   if (content_type_->SupportsGroup(
           ContextMenuContentType::ITEM_GROUP_PASSWORD)) {
     AppendPasswordItems();
@@ -947,6 +945,11 @@ void RenderViewContextMenu::InitMenu() {
   if (added_accessibility_labels_items && menu_model_.GetItemCount() == 1) {
     menu_model_.RemoveItemAt(0);
   }
+
+  // Always add Quick Answers view last, as it is rendered next to the context
+  // menu, meaning that each menu item added/removed in this function will cause
+  // it to visibly jump on the screen (see b/173569669).
+  AppendQuickAnswersItems();
 }
 
 Profile* RenderViewContextMenu::GetProfile() const {