Bug 1867811 - Expose EXPANDED state for element with popovertarget. r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D196541

accessible/base/nsAccessibilityService.cpp

@@ -716,6 +716,19 @@ void nsAccessibilityService::TableLayoutGuessMaybeChanged(
   }
 }
 
+void nsAccessibilityService::PopovertargetMaybeChanged(PresShell* aPresShell,
+                                                       nsIContent* aContent) {
+  DocAccessible* document = GetDocAccessible(aPresShell);
+  if (!document) {
+    return;
+  }
+  if (LocalAccessible* acc = document->GetAccessible(aContent)) {
+    RefPtr<AccEvent> expandedChangeEvent =
+        new AccStateChangeEvent(acc, states::EXPANDED);
+    document->FireDelayedEvent(expandedChangeEvent);
+  }
+}
+
 void nsAccessibilityService::ComboboxOptionMaybeChanged(
     PresShell* aPresShell, nsIContent* aMutatingNode) {
   DocAccessible* document = GetDocAccessible(aPresShell);

accessible/base/nsAccessibilityService.h

@@ -180,6 +180,12 @@ class nsAccessibilityService final : public mozilla::a11y::DocManager,
   void TableLayoutGuessMaybeChanged(mozilla::PresShell* aPresShell,
                                     nsIContent* aContent);
 
+  /**
+   * Notifies when an element's popovertarget shows/hides.
+   */
+  void PopovertargetMaybeChanged(mozilla::PresShell* aPresShell,
+                                 nsIContent* aContent);
+
   /**
    * Notifies when a combobox <option> text or label changes.
    */

accessible/html/HTMLFormControlAccessible.cpp

@@ -178,6 +178,15 @@ void HTMLButtonAccessible::ActionNameAt(uint8_t aIndex, nsAString& aName) {
 uint64_t HTMLButtonAccessible::NativeState() const {
   uint64_t state = HyperTextAccessible::NativeState();
 
+  dom::Element* elm = Elm();
+  if (auto* popover = elm->GetEffectivePopoverTargetElement()) {
+    if (popover->IsPopoverOpen()) {
+      state |= states::EXPANDED;
+    } else {
+      state |= states::COLLAPSED;
+    }
+  }
+
   ElementState elmState = mContent->AsElement()->State();
   if (elmState.HasState(ElementState::DEFAULT)) state |= states::DEFAULT;
 

accessible/tests/browser/e10s/browser_caching_states.js

@@ -482,3 +482,33 @@ addAccessibleTask(
   },
   { chrome: true, topLevel: true, remoteIframe: true }
 );
+
+/**
+ * Test caching of the expanded state for popover target element.
+ */
+addAccessibleTask(
+  `
+  <button id="show-popover-btn" popovertarget="mypopover" popovertargetaction="show">Show popover</button>
+  <button id="hide-popover-btn" popovertarget="mypopover" popovertargetaction="hide">Hide popover</button>
+  <div id="mypopover" popover>Popover content</div>
+  `,
+  async function (browser, docAcc) {
+    const show = findAccessibleChildByID(docAcc, "show-popover-btn");
+    const hide = findAccessibleChildByID(docAcc, "hide-popover-btn");
+    testStates(show, STATE_COLLAPSED, 0);
+    testStates(hide, STATE_COLLAPSED, 0);
+
+    info("Expanding popover");
+    let onShowing = waitForEvent(EVENT_STATE_CHANGE, show);
+    await show.doAction(0);
+    let showingEvent = await onShowing;
+    testStates(showingEvent.accessible, STATE_EXPANDED, 0);
+
+    info("Collapsing popover");
+    let onHiding = waitForEvent(EVENT_STATE_CHANGE, hide);
+    await hide.doAction(0);
+    let hidingEvent = await onHiding;
+    testStates(hidingEvent.accessible, STATE_COLLAPSED, 0);
+  },
+  { chrome: true, topLevel: true, remoteIframe: true }
+);

dom/html/nsGenericHTMLElement.cpp

@@ -93,6 +93,10 @@
 #include "mozilla/dom/ElementBinding.h"
 #include "mozilla/dom/ElementInternals.h"
 
+#ifdef ACCESSIBILITY
+#  include "nsAccessibilityService.h"
+#endif
+
 using namespace mozilla;
 using namespace mozilla::dom;
 
@@ -2853,14 +2857,28 @@ void nsGenericHTMLFormControlElementWithState::HandlePopoverTargetAction() {
 
   bool canHide = action == PopoverTargetAction::Hide ||
                  action == PopoverTargetAction::Toggle;
+  bool shouldHide = canHide && target->IsPopoverOpen();
   bool canShow = action == PopoverTargetAction::Show ||
                  action == PopoverTargetAction::Toggle;
+  bool shouldShow = canShow && !target->IsPopoverOpen();
 
-  if (canHide && target->IsPopoverOpen()) {
+  if (shouldHide) {
     target->HidePopover(IgnoreErrors());
-  } else if (canShow && !target->IsPopoverOpen()) {
+  } else if (shouldShow) {
     target->ShowPopoverInternal(this, IgnoreErrors());
   }
+#ifdef ACCESSIBILITY
+  // Notify the accessibility service about the change.
+  if (shouldHide || shouldShow) {
+    if (RefPtr<Document> doc = GetComposedDoc()) {
+      if (PresShell* presShell = doc->GetPresShell()) {
+        if (nsAccessibilityService* accService = GetAccService()) {
+          accService->PopovertargetMaybeChanged(presShell, this);
+        }
+      }
+    }
+  }
+#endif
 }
 
 void nsGenericHTMLFormControlElementWithState::GetInvokeAction(