Add optional force parameter to togglePopover

This was suggested by domenic here:
whatwg/html#8221 (comment)

Bug: 1307772
Change-Id: Ie371028dd41601f445b7590d0769e6bf101f6072
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4070786
Commit-Queue: Mason Freed <[email protected]>
Reviewed-by: Mason Freed <[email protected]>
Commit-Queue: Joey Arhar <[email protected]>
Auto-Submit: Joey Arhar <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1081666}

html/semantics/popovers/popover-attribute-basic.tentative.html

@@ -84,6 +84,14 @@
     assertPopoverVisibility(popover, /*isPopover*/true, /*expectedVisibility*/true, 'After togglePopover() on hidden popover, it should be visible');
     popover.togglePopover();
     assertPopoverVisibility(popover, /*isPopover*/true, /*expectedVisibility*/false, 'After togglePopover() on visible popover, it should be hidden');
+    popover.togglePopover(/*force=*/true);
+    assertPopoverVisibility(popover, /*isPopover*/true, /*expectedVisibility*/true, 'After togglePopover(true) on hidden popover, it should be visible');
+    popover.togglePopover(/*force=*/true);
+    assertPopoverVisibility(popover, /*isPopover*/true, /*expectedVisibility*/true, 'After togglePopover(true) on visible popover, it should be visible');
+    popover.togglePopover(/*force=*/false);
+    assertPopoverVisibility(popover, /*isPopover*/true, /*expectedVisibility*/false, 'After togglePopover(false) on visible popover, it should be hidden');
+    popover.togglePopover(/*force=*/false);
+    assertPopoverVisibility(popover, /*isPopover*/true, /*expectedVisibility*/false, 'After togglePopover(false) on hidden popover, it should be hidden');
     const parent = popover.parentElement;
     popover.remove();
     assert_throws_dom("InvalidStateError",() => popover.showPopover(),'Calling showPopover on a disconnected popover should throw InvalidStateError');