From 46a5a2a57ad313f764e899aa128b7b6b00469e72 Mon Sep 17 00:00:00 2001
From: Amelia Hart <ame@psianesia.org>
Date: Fri, 26 Sep 2025 11:00:06 +0200
Subject: [PATCH] Implement cycle collection support for the Visual Viewport
 API

---
 dom/base/VisualViewport.cpp | 16 ++++++++++++++++
 dom/base/VisualViewport.h   |  3 +++
 dom/base/nsGlobalWindow.cpp |  2 ++
 3 files changed, 21 insertions(+)

diff --git a/dom/base/VisualViewport.cpp b/dom/base/VisualViewport.cpp
index c33b1dbf5f..9efe4c7545 100644
--- a/dom/base/VisualViewport.cpp
+++ b/dom/base/VisualViewport.cpp
@@ -25,6 +25,22 @@ VisualViewport::~VisualViewport()
 {
 }
 
+NS_IMPL_CYCLE_COLLECTION_CLASS(VisualViewport)
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(VisualViewport,
+                                                  DOMEventTargetHelper)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(VisualViewport,
+                                                DOMEventTargetHelper)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(VisualViewport)
+NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
+
+NS_IMPL_ADDREF_INHERITED(VisualViewport, DOMEventTargetHelper)
+NS_IMPL_RELEASE_INHERITED(VisualViewport, DOMEventTargetHelper)
+
 /* virtual */
 JSObject*
 VisualViewport::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
diff --git a/dom/base/VisualViewport.h b/dom/base/VisualViewport.h
index 720b368726..c9d39b577a 100644
--- a/dom/base/VisualViewport.h
+++ b/dom/base/VisualViewport.h
@@ -21,6 +21,9 @@ class VisualViewport final: public mozilla::DOMEventTargetHelper
 {
 
 public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(VisualViewport, DOMEventTargetHelper)
+
   explicit VisualViewport(nsPIDOMWindowInner* aWindow);
   explicit VisualViewport(nsIGlobalObject* aGlobal);
 
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 3a0d89f1b5..4685c50136 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -2183,6 +2183,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(nsGlobalWindow)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mLocation)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mHistory)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCustomElements)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mVisualViewport)
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mLocalStorage)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSessionStorage)
@@ -2261,6 +2262,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsGlobalWindow)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mLocation)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mHistory)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mCustomElements)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mVisualViewport)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mLocalStorage)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mSessionStorage)
   if (tmp->mApplicationCache) {