Tab Search bug fix - Search field focus to restore item selection

When the search field gains focus, if there are any tab items present
one should be in a selected state

Fixed: 1128616
Change-Id: I5290e7609a03ad2239660dd940bcb79cc30c6663
Reviewed-on: https://chrome-internal-review.googlesource.com/c/chrome/browser/resources/tab_search/+/3272424Reviewed-by: John Lee <johntlee@chromium.org>
Reviewed-by: Tom Lukaszewicz <tluk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819602}

chrome/browser/resources/tab_search_merge/app.html

@@ -55,8 +55,8 @@
   </svg>
 </iron-iconset-svg>
 <tab-search-search-field id="searchField" autofocus clear-label="Clear search"
-    label="Search tabs [[getKeyboardShortcut_()]]" on-keydown="onSearchKeyDown_"
-    on-search-changed="onSearchChanged_">
+    label="Search tabs [[getKeyboardShortcut_()]]" on-focus="onSearchFocus_"
+    on-keydown="onSearchKeyDown_" on-search-changed="onSearchChanged_">
 </tab-search-search-field>
 <div id="tabs">
   <iron-selector id="selector" on-keydown="onItemKeyDown_"

chrome/browser/resources/tab_search_merge/app.js

@@ -271,6 +271,14 @@ export class TabSearchAppElement extends PolymerElement {
     }
   }
 
+  /** @private */
+  onSearchFocus_() {
+    if (this.$.selector.selected === undefined &&
+        this.filteredOpenTabs_.length > 0) {
+      this.$.selector.selectIndex(0);
+    }
+  }
+
   /**
    * Handles key events when the search field has focus.
    * @param {!KeyboardEvent} e

chrome/browser/resources/tab_search_merge/test/tab_search_app_focus_test.js

@@ -58,6 +58,17 @@ suite('TabSearchAppFocusTest', () => {
 
     keyDownOn(tabSearchItems[tabSearchItems.length - 1], 0, [], 'Home');
     assertEquals(tabSearchItems[0], getDeepActiveElement());
+
+    // Once the feedback button is focused, no list item should be selected.
+    const feedbackButton = /** @type {!HTMLElement} */ (
+        tabSearchApp.shadowRoot.querySelector('#feedback-footer'));
+    feedbackButton.focus();
+    assertEquals(-1, tabSearchApp.getSelectedIndex());
+
+    // On restoring focus to the search field, a list item should be selected if
+    // available.
+    searchInput.focus();
+    assertEquals(0, tabSearchApp.getSelectedIndex());
   });
 
   test('KeyPress', async () => {