Fixes bug where Omnibox input wouldn't update on selecting the first ZPS

Currently Omnibox would clear the temporary text if the first results is
attempted to be selected using the arrow key. This prevents the first
zero-prefix result from being selected as there is no default matches in
that case. This CL fixes that by adding an extra condition to prevent
selection when there's no editing.

Bug: 996516
Change-Id: Idb3338fcc86233ce14f0de22dc4253691f5daf13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1845913Reviewed-by: Tommy Li <tommycli@chromium.org>
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#703487}

components/omnibox/browser/omnibox_edit_model.cc

@@ -1179,7 +1179,7 @@ void OmniboxEditModel::OnUpOrDownKeyPressed(int count) {
     // we should revert the temporary text same as what pressing escape would
     // have done.
     const size_t line_no = GetNewSelectedLine(count);
-    if (has_temporary_text_ && line_no == 0) {
+    if (has_temporary_text_ && user_input_in_progress_ && line_no == 0) {
       RevertTemporaryText(true);
     } else {
       popup_model()->MoveTo(line_no);