WebUI: cr-radio-group, wrap selections when using keyboard input

Bug: 949080
Change-Id: Ibe39efccf103abc627efbdee8b892720a4c265ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1595301
Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Commit-Queue: Esmael El-Moslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#656628}

chrome/test/data/webui/cr_elements/cr_radio_group_test.js

@@ -96,11 +96,15 @@ suite('cr-radio-group', () => {
     // Check for decrement.
     checkPressed(['Home', 'PageUp', 'ArrowUp', 'ArrowLeft'], 2, 1);
     // No change when reached first selected.
-    checkPressed(['Home', 'PageUp', 'ArrowUp', 'ArrowLeft'], 1, 1);
+    checkPressed(['Home'], 1, 1);
+    // Wraps when decrementing when first selected.
+    checkPressed(['PageUp', 'ArrowUp', 'ArrowLeft'], 1, 3);
     // Check for increment.
     checkPressed(['End', 'ArrowRight', 'PageDown', 'ArrowDown'], 2, 3);
     // No change when reached last selected.
-    checkPressed(['End', 'ArrowRight', 'PageDown', 'ArrowDown'], 3, 3);
+    checkPressed(['End'], 3, 3);
+    // Wraps when incrementing when last selected.
+    checkPressed(['ArrowRight', 'PageDown', 'ArrowDown'], 3, 1);
   });
 
   test('mouse event', () => {

ui/webui/resources/cr_elements/cr_radio_group/cr_radio_group.js

@@ -164,7 +164,12 @@
         // If nothing selected, start from the first radio then add |delta|.
         const lastSelection = enabledRadios.findIndex(radio => radio.checked);
         selectedIndex = Math.max(0, lastSelection) + delta;
-        selectedIndex = Math.min(max, Math.max(0, selectedIndex));
+        // Wrap the selection, if needed.
+        if (selectedIndex > max) {
+          selectedIndex = 0;
+        } else if (selectedIndex < 0) {
+          selectedIndex = max;
+        }
       } else {
         return;
       }