Tab Search: Check for key modifiers before navigation

Check for key event modifires before triggering keyboard navigation.

Fixed: 1111003
Change-Id: Icccfc2938d4812974b628273edc7d68fc825a559
Reviewed-on: https://chrome-internal-review.googlesource.com/c/chrome/browser/resources/tab_search/+/3202978Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Tom Lukaszewicz <tluk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819580}

chrome/browser/resources/tab_search_merge/app.js

@@ -145,26 +145,39 @@ export class TabSearchAppElement extends PolymerElement {
   }
 
   /**
-   * TODO(crbug.com/1111003): Check for the presence of modifiers before
-   * triggering a navigation.
    * @param {!KeyboardEvent} e
    * @private
    */
   onKeyDown_(e) {
-    if (this.selectedIndex_ !== -1) {
+    // Do not interfere with the search field's management of text selection.
+    if (e.shiftKey) {
+      return;
+    }
+
+    e.stopPropagation();
+
+    if (this.selectedIndex_ === -1) {
+      // No tabs matching the search text criteria.
+      return;
+    }
+
     switch (e.key) {
       case 'ArrowUp':
         this.selectItem_(-1);
+        e.preventDefault();
         break;
       case 'ArrowDown':
         this.selectItem_(1);
+        e.preventDefault();
         break;
       case 'Home':
         this.selectItem_(-this.selectedIndex_);
+        e.preventDefault();
         break;
       case 'End':
         this.selectItem_(
             this.filteredOpenTabs_.length - 1 - this.selectedIndex_);
+        e.preventDefault();
         break;
       case 'Enter':
         const selectedItem = this.filteredOpenTabs_[this.selectedIndex_];
@@ -173,9 +186,6 @@ export class TabSearchAppElement extends PolymerElement {
     }
   }
 
-    e.stopPropagation();
-  }
-
   /**
    * @param {number} offset Distance from the desired item to select and the
    *     currently selected item.

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

@@ -177,6 +177,18 @@ suite('TabSearchAppTest', () => {
     assertEquals(0, tabSearchApp.getSelectedIndex());
   });
 
+  test('Key with modifiers should not affect selected item', async () => {
+    await setupTest(sampleData());
+
+    const searchField = /** @type {!TabSearchSearchField} */
+        (tabSearchApp.shadowRoot.querySelector('#searchField'));
+
+    for (const key of ['ArrowUp', 'ArrowDown', 'Home', 'End']) {
+      keyDownOn(searchField, 0, ['shift'], key);
+      assertEquals(0, tabSearchApp.getSelectedIndex());
+    }
+  });
+
   test('refresh on tabs changed', async () => {
     await setupTest(sampleData());
     verifyTabIds(queryRows(), [1, 5, 6, 2, 3, 4]);