Update popover post-toggle event naming and behavior

This CL updates the post-toggle event in the following ways:
 1. Rename the 'aftertoggle' event to 'toggle'.
 2. Rename PopoverToggleEvent to ToggleEvent.
 3. Rename the currentState attribute to oldState.
 4. Add event coalescing behavior. If two transitions occur before the
    first 'toggle' event has been fired, cancel the first event and
    queue a replacement that has oldState === newState.

These changes were driven by the corresponding changes to the spec PR:
  whatwg/html#8717

Bug: 1307772
Change-Id: Iabc5a9093d7cef3bbd6e54e488d8e571c51ea568
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4195120
Auto-Submit: Mason Freed <masonf@chromium.org>
Commit-Queue: Joey Arhar <jarhar@chromium.org>
Reviewed-by: Joey Arhar <jarhar@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1098728}

Author: mfreed7

html/semantics/popovers/idlharness.tentative.html

@@ -41,12 +41,12 @@
         'document.getElementById("b3")',
       ],
       BeforeToggleEvent: [
-        'new PopoverToggleEvent("beforetoggle")',
-        'new PopoverToggleEvent("beforetoggle", {currentState: "open"})',
-        'new PopoverToggleEvent("beforetoggle", {currentState: "open",newState: "open"})',
-        'new PopoverToggleEvent("aftertoggle")',
-        'new PopoverToggleEvent("aftertoggle", {currentState: "open"})',
-        'new PopoverToggleEvent("aftertoggle", {currentState: "open",newState: "open"})',
+        'new ToggleEvent("beforetoggle")',
+        'new ToggleEvent("beforetoggle", {oldState: "open"})',
+        'new ToggleEvent("beforetoggle", {oldState: "open",newState: "open"})',
+        'new ToggleEvent("toggle")',
+        'new ToggleEvent("toggle", {oldState: "open"})',
+        'new ToggleEvent("toggle", {oldState: "open",newState: "open"})',
       ],
     });
   }

html/semantics/popovers/popover-events.tentative.html

@@ -10,6 +10,13 @@
 <div popover>Popover</div>
 
 <script>
+function getPopoverAndSignal(t) {
+  const popover = document.querySelector('[popover]');
+  const controller = new AbortController();
+  const signal = controller.signal;
+  t.add_cleanup(() => controller.abort());
+  return {popover, signal};
+}
 window.onload = () => {
   for(const method of ["listener","attribute"]) {
     promise_test(async t => {
@@ -22,52 +29,48 @@
       function listener(e) {
         if (e.type === "beforetoggle") {
           if (e.newState === "open") {
-            assert_equals(e.currentState,"closed",'The "beforetoggle" event should be fired before the popover is open');
+            ++showCount;
+            assert_equals(e.oldState,"closed",'The "beforetoggle" event should be fired before the popover is open');
             assert_true(e.target.matches(':closed'),'The popover should be in the :closed state when the opening event fires.');
             assert_false(e.target.matches(':open'),'The popover should *not* be in the :open state when the opening event fires.');
-            ++showCount;
           } else {
+            ++hideCount;
             assert_equals(e.newState,"closed",'Popover toggleevent states should be "open" and "closed"');
-            assert_equals(e.currentState,"open",'The "beforetoggle" event should be fired before the popover is closed')
+            assert_equals(e.oldState,"open",'The "beforetoggle" event should be fired before the popover is closed')
             assert_true(e.target.matches(':open'),'The popover should be in the :open state when the hiding event fires.');
             assert_false(e.target.matches(':closed'),'The popover should *not* be in the :closed state when the hiding event fires.');
-            ++hideCount;
           }
         } else {
-          assert_equals(e.type,"aftertoggle",'Popover events should be "beforetoggle" and "aftertoggle"')
+          assert_equals(e.type,"toggle",'Popover events should be "beforetoggle" and "toggle"')
           if (e.newState === "open") {
-            assert_equals(e.currentState,"open",'Aftertoggle should be fired after the popover is open');
+            ++afterShowCount;
             if (document.body.contains(e.target)) {
               assert_true(e.target.matches(':open'),'The popover should be in the :open state when the after opening event fires.');
               assert_false(e.target.matches(':closed'),'The popover should *not* be in the :closed state when the after opening event fires.');
             }
-            ++afterShowCount;
           } else {
+            ++afterHideCount;
             assert_equals(e.newState,"closed",'Popover toggleevent states should be "open" and "closed"');
-            assert_equals(e.currentState,"closed",'Aftertoggle should be fired after the popover is closed');
             assert_true(e.target.matches(':closed'),'The popover should be in the :closed state when the after hiding event fires.');
             assert_false(e.target.matches(':open'),'The popover should *not* be in the :open state when the after hiding event fires.');
-            ++afterHideCount;
           }
-          e.preventDefault(); // "aftertoggle" should not be cancelable.
+          e.preventDefault(); // "toggle" should not be cancelable.
         }
       };
       switch (method) {
         case "listener":
-          const controller = new AbortController();
-          const signal = controller.signal;
-          t.add_cleanup(() => controller.abort());
+          const {signal} = getPopoverAndSignal(t);
           // These events bubble.
           document.addEventListener('beforetoggle', listener, {signal});
-          document.addEventListener('aftertoggle', listener, {signal});
+          document.addEventListener('toggle', listener, {signal});
           break;
         case "attribute":
           assert_false(popover.hasAttribute('onbeforetoggle'));
           t.add_cleanup(() => popover.removeAttribute('onbeforetoggle'));
           popover.onbeforetoggle = listener;
-          assert_false(popover.hasAttribute('onaftertoggle'));
-          t.add_cleanup(() => popover.removeAttribute('onaftertoggle'));
-          popover.onaftertoggle = listener;
+          assert_false(popover.hasAttribute('ontoggle'));
+          t.add_cleanup(() => popover.removeAttribute('ontoggle'));
+          popover.ontoggle = listener;
           break;
         default: assert_unreached();
       }
@@ -82,7 +85,7 @@
       assert_equals(0,afterShowCount);
       assert_equals(0,afterHideCount);
       await waitForRender();
-      assert_equals(1,afterShowCount,'aftertoggle show is fired asynchronously');
+      assert_equals(1,afterShowCount,'toggle show is fired asynchronously');
       assert_equals(0,afterHideCount);
       assert_true(popover.matches(':open'));
       popover.hidePopover();
@@ -93,7 +96,7 @@
       assert_equals(0,afterHideCount);
       await waitForRender();
       assert_equals(1,afterShowCount);
-      assert_equals(1,afterHideCount,'aftertoggle hide is fired asynchronously');
+      assert_equals(1,afterHideCount,'toggle hide is fired asynchronously');
       // No additional events
       await waitForRender();
       await waitForRender();
@@ -106,10 +109,7 @@
   }
 
   promise_test(async t => {
-    const popover = document.querySelector('[popover]');
-    const controller = new AbortController();
-    const signal = controller.signal;
-    t.add_cleanup(() => controller.abort());
+    const {popover,signal} = getPopoverAndSignal(t);
     let cancel = true;
     popover.addEventListener('beforetoggle',(e) => {
       if (e.newState !== "open")
@@ -128,10 +128,7 @@
   }, 'The "beforetoggle" event is cancelable for the "opening" transition');
 
   promise_test(async t => {
-    const popover = document.querySelector('[popover]');
-    const controller = new AbortController();
-    const signal = controller.signal;
-    t.add_cleanup(() => {controller.abort();});
+    const {popover,signal} = getPopoverAndSignal(t);
     popover.addEventListener('beforetoggle',(e) => {
       assert_not_equals(e.newState,"closed",'The "beforetoggle" event was fired for the closing transition');
     }, {signal});
@@ -144,5 +141,74 @@
     await waitForRender(); // Check for async events also
     assert_false(popover.matches(':open'));
   }, 'The "beforetoggle" event is not fired for element removal');
+
+  promise_test(async t => {
+    const {popover,signal} = getPopoverAndSignal(t);
+    let events;
+    function resetEvents() {
+      events = {
+        singleShow: false,
+        singleHide: false,
+        coalescedShow: false,
+        coalescedHide: false,
+      };
+    }
+    function setEvent(type) {
+      assert_equals(events[type],false,'event repeated');
+      events[type] = true;
+    }
+    function assertOnly(type,msg) {
+      Object.keys(events).forEach(val => {
+        assert_equals(events[val],val===type,`${msg} (${val})`);
+      });
+    }
+    popover.addEventListener('toggle',(e) => {
+      switch (e.newState) {
+        case "open":
+          switch (e.oldState) {
+            case "open": setEvent('coalescedShow'); break;
+            case "closed": setEvent('singleShow'); break;
+            default: assert_unreached();
+          }
+          break;
+        case "closed":
+          switch (e.oldState) {
+            case "closed": setEvent('coalescedHide'); break;
+            case "open": setEvent('singleHide'); break;
+            default: assert_unreached();
+          }
+          break;
+        default: assert_unreached();
+      }
+    }, {signal});
+
+    resetEvents();
+    assertOnly('none');
+    assert_false(popover.matches(':open'));
+    popover.showPopover();
+    await waitForRender();
+    assert_true(popover.matches(':open'));
+    assertOnly('singleShow','Single event should have been fired, which is a "show"');
+
+    resetEvents();
+    popover.hidePopover();
+    popover.showPopover(); // Immediate re-show
+    await waitForRender();
+    assert_true(popover.matches(':open'));
+    assertOnly('coalescedShow','Single coalesced event should have been fired, which is a "show"');
+
+    resetEvents();
+    popover.hidePopover();
+    await waitForRender();
+    assertOnly('singleHide','Single event should have been fired, which is a "hide"');
+    assert_false(popover.matches(':open'));
+
+    resetEvents();
+    popover.showPopover();
+    popover.hidePopover(); // Immediate re-hide
+    await waitForRender();
+    assertOnly('coalescedHide','Single coalesced event should have been fired, which is a "hide"');
+    assert_false(popover.matches(':open'));
+  }, 'The "toggle" event is coalesced');
 };
 </script>