Bug 1762152 - Remove XULPopupElement.isAnchored. r=Gijs

On Wayland popup flipping and such is not Firefox's responsibility.

Once we've decided the final popup position because the compositor told
us, we move the popup to a fixed position, and internally the popup
becomes unanchored.

Using this boolean to make decisions after the initial popuppositioned
event is wrong, so avoid exposing it to JS.

Differential Revision: https://phabricator.services.mozilla.com/D142679

dom/webidl/PopupPositionedEvent.webidl

@@ -5,6 +5,7 @@
  */
 
 dictionary PopupPositionedEventInit : EventInit {
+  boolean isAnchored = false;
   /**
    * Returns the alignment position where the popup has appeared relative to its
    * anchor node or point, accounting for any flipping that occurred.
@@ -17,6 +18,7 @@ dictionary PopupPositionedEventInit : EventInit {
 interface PopupPositionedEvent : Event {
   constructor(DOMString type, optional PopupPositionedEventInit init = {});
 
+  readonly attribute boolean isAnchored;
   readonly attribute DOMString alignmentPosition;
   readonly attribute long alignmentOffset;
 };

dom/webidl/XULPopupElement.webidl

@@ -167,12 +167,6 @@ interface XULPopupElement : XULElement
    */
   readonly attribute Node? triggerNode;
 
-  /**
-   * True if the popup is anchored to a point or rectangle. False if it
-   * appears at a fixed screen coordinate.
-   */
-  readonly attribute boolean isAnchored;
-
   /**
    * Retrieve the anchor that was specified to openPopup or for menupopups in a
    * menu, the parent menu.

dom/xul/XULPopupElement.cpp

@@ -237,22 +237,12 @@ nsINode* XULPopupElement::GetTriggerNode() const {
   return nsMenuPopupFrame::GetTriggerContent(menuPopupFrame);
 }
 
-bool XULPopupElement::IsAnchored() const {
-  nsMenuPopupFrame* menuPopupFrame = do_QueryFrame(GetPrimaryFrame());
-  if (!menuPopupFrame) {
-    return false;
-  }
-
-  return menuPopupFrame->IsAnchored();
-}
-
 // FIXME(emilio): should probably be renamed to GetAnchorElement?
 Element* XULPopupElement::GetAnchorNode() const {
   nsMenuPopupFrame* menuPopupFrame = do_QueryFrame(GetPrimaryFrame());
   if (!menuPopupFrame) {
     return nullptr;
   }
-
   return Element::FromNodeOrNull(menuPopupFrame->GetAnchor());
 }
 

dom/xul/XULPopupElement.h

@@ -77,8 +77,6 @@ class XULPopupElement : public nsXULElement {
 
   nsINode* GetTriggerNode() const;
 
-  bool IsAnchored() const;
-
   Element* GetAnchorNode() const;
 
   already_AddRefed<DOMRect> GetOuterScreenRect();

layout/xul/nsXULPopupManager.cpp

@@ -2932,6 +2932,7 @@ nsXULPopupPositionedEvent::Run() {
 
   PopupPositionedEventInit init;
   init.mComposed = true;
+  init.mIsAnchored = popupFrame->IsAnchored();
   init.mAlignmentOffset = popupOffset;
   AlignmentPositionToString(popupFrame, init.mAlignmentPosition);
   RefPtr<PopupPositionedEvent> event =

toolkit/content/widgets/panel.js

@@ -92,7 +92,7 @@
     }
 
     _setSideAttribute(event) {
-      if (!this.isArrowPanel || !this.isAnchored) {
+      if (!this.isArrowPanel || !event.isAnchored) {
         return;
       }
 
@@ -123,7 +123,7 @@
         this.panelContent.style.display = "";
       }
       if (this.isArrowPanel && event.target == this) {
-        if (this.isAnchored && this.anchorNode) {
+        if (this.anchorNode) {
           let anchorRoot =
             this.anchorNode.closest("toolbarbutton, .anchor-root") ||
             this.anchorNode;
@@ -194,7 +194,7 @@
           this.setAttribute("animate", "cancel");
         }
 
-        if (this.isAnchored && this.anchorNode) {
+        if (this.anchorNode) {
           let anchorRoot =
             this.anchorNode.closest("toolbarbutton, .anchor-root") ||
             this.anchorNode;