Ensure Undo/Redo are shown in context menu when Emoji is shown.

Currently Undo/Redo are not added when there are menu items before it.
This was to deal with autocorrect/selected text items. However, when
we add Emoji as a menu item, we still want Undo/Redo to show. This
patch makes an exception for this.

Test: Is tested in crrev/1090408
Bug: See crrev/1090408
Change-Id: I960e064e2829e97b61e6fa8be31091dd6f671f24
Reviewed-on: https://chromium-review.googlesource.com/1092214
Commit-Queue: Mathieu Perreault <mathp@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565675}

chrome/browser/renderer_context_menu/render_view_context_menu.cc

@@ -1434,8 +1434,12 @@ void RenderViewContextMenu::AppendEditableItems() {
                                   IDS_CONTENT_CONTEXT_REDO);
   menu_model_.AddSeparator(ui::NORMAL_SEPARATOR);
 #else
-  if (!IsDevToolsURL(params_.page_url) && !menu_model_.GetItemCount() &&
-      !content_type_->SupportsGroup(ContextMenuContentType::ITEM_GROUP_PRINT)) {
+  // Also want to show 'Undo' and 'Redo' if 'Emoji' is the only item in the menu
+  // so far.
+  if (!IsDevToolsURL(params_.page_url) &&
+      !content_type_->SupportsGroup(ContextMenuContentType::ITEM_GROUP_PRINT) &&
+      (!menu_model_.GetItemCount() ||
+       menu_model_.GetIndexOfCommandId(IDC_CONTENT_CONTEXT_EMOJI) != -1)) {
     menu_model_.AddItemWithStringId(IDC_CONTENT_CONTEXT_UNDO,
                                     IDS_CONTENT_CONTEXT_UNDO);
     menu_model_.AddItemWithStringId(IDC_CONTENT_CONTEXT_REDO,