Bug 1821732 - implement auto popover list, r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D172296

dom/base/Document.cpp

@@ -14574,11 +14574,7 @@ void Document::SetFullscreenElement(Element& aElement) {
 void Document::TopLayerPush(Element& aElement) {
   const bool modal = aElement.State().HasState(ElementState::MODAL);
 
-  auto predictFunc = [&aElement](Element* element) {
+  TopLayerPop(aElement);
-    return element == &aElement;
-  };
-  TopLayerPop(predictFunc);
-
   mTopLayer.AppendElement(do_GetWeakReference(&aElement));
   NS_ASSERTION(GetTopLayerTop() == &aElement, "Should match");
 
@@ -14614,10 +14610,7 @@ void Document::AddModalDialog(HTMLDialogElement& aDialogElement) {
 }
 
 void Document::RemoveModalDialog(HTMLDialogElement& aDialogElement) {
-  auto predicate = [&aDialogElement](Element* element) -> bool {
+  DebugOnly<Element*> removedElement = TopLayerPop(aDialogElement);
-    return element == &aDialogElement;
-  };
-  DebugOnly<Element*> removedElement = TopLayerPop(predicate);
   MOZ_ASSERT(removedElement == &aDialogElement);
   aDialogElement.RemoveStates(ElementState::MODAL);
 }
@@ -14685,6 +14678,13 @@ Element* Document::TopLayerPop(FunctionRef<bool(Element*)> aPredicate) {
   return removedElement;
 }
 
+Element* Document::TopLayerPop(Element& aElement) {
+  auto predictFunc = [&aElement](Element* element) {
+    return element == &aElement;
+  };
+  return TopLayerPop(predictFunc);
+}
+
 void Document::GetWireframe(bool aIncludeNodes,
                             Nullable<Wireframe>& aWireframe) {
   FlushPendingNotifications(FlushType::Layout);
@@ -14826,6 +14826,38 @@ nsTArray<Element*> Document::GetTopLayer() const {
   return elements;
 }
 
+nsTArray<Element*> Document::AutoPopoverList() const {
+  nsTArray<Element*> elements;
+  for (const nsWeakPtr& ptr : mTopLayer) {
+    if (nsCOMPtr<Element> element = do_QueryReferent(ptr)) {
+      if (element && element->IsAutoPopover()) {
+        elements.AppendElement(element);
+      }
+    }
+  }
+  return elements;
+}
+
+Element* Document::GetTopmostAutoPopover() const {
+  for (const nsWeakPtr& weakPtr : Reversed(mTopLayer)) {
+    nsCOMPtr<Element> element(do_QueryReferent(weakPtr));
+    if (element && element->IsAutoPopover()) {
+      return element;
+    }
+  }
+  return nullptr;
+}
+
+void Document::AddToAutoPopoverList(Element& aElement) {
+  MOZ_ASSERT(aElement.IsAutoPopover());
+  TopLayerPush(aElement);
+}
+
+void Document::RemoveFromAutoPopoverList(Element& aElement) {
+  MOZ_ASSERT(aElement.IsAutoPopover());
+  TopLayerPop(aElement);
+}
+
 // Returns true if aDoc is in the focused tab in the active window.
 bool IsInActiveTab(Document* aDoc) {
   BrowsingContext* bc = aDoc->GetBrowsingContext();

dom/base/Document.h

@@ -1927,6 +1927,10 @@ class Document : public nsINode,
   // layer. The removed element, if any, is returned.
   Element* TopLayerPop(FunctionRef<bool(Element*)> aPredicate);
 
+  // Removes the given element from the top layer. The removed element, if any,
+  // is returned.
+  Element* TopLayerPop(Element&);
+
   MOZ_CAN_RUN_SCRIPT bool TryAutoFocusCandidate(Element& aElement);
 
  public:
@@ -3449,6 +3453,20 @@ class Document : public nsINode,
   MOZ_CAN_RUN_SCRIPT void GetWireframe(bool aIncludeNodes,
                                        Nullable<Wireframe>&);
 
+  // Returns a list of all the elements in the Document's top layer whose
+  // popover attribute is in the auto state.
+  // See https://html.spec.whatwg.org/multipage/popover.html#auto-popover-list
+  nsTArray<Element*> AutoPopoverList() const;
+
+  // Teturn document's auto popover list's last element.
+  // See
+  // https://html.spec.whatwg.org/multipage/popover.html#topmost-auto-popover
+  Element* GetTopmostAutoPopover() const;
+
+  // Adds/removes an element to/from the auto popover list.
+  void AddToAutoPopoverList(Element&);
+  void RemoveFromAutoPopoverList(Element&);
+
   Element* GetTopLayerTop();
   // Return the fullscreen element in the top layer
   Element* GetUnretargetedFullscreenElement() const;

dom/base/Element.cpp

@@ -4205,6 +4205,11 @@ void Element::ClearServoData(Document* aDoc) {
   }
 }
 
+bool Element::IsAutoPopover() const {
+  const auto* htmlElement = nsGenericHTMLElement::FromNode(this);
+  return htmlElement && htmlElement->GetPopoverState() == PopoverState::Auto;
+}
+
 ElementAnimationData& Element::CreateAnimationData() {
   MOZ_ASSERT(!GetAnimationData());
   SetMayHaveAnimations();

dom/base/Element.h

@@ -580,6 +580,8 @@ class Element : public FragmentOrElement {
     return CreatePopoverData();
   }
 
+  bool IsAutoPopover() const;
+
   ElementAnimationData* GetAnimationData() const {
     if (!MayHaveAnimations()) {
       return nullptr;