[wrapper-tracing] Trace CustomElementReactionStack

third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
index 3a81125943c0778c94215d4fd75beebe0e903ec9..1250ed12777b73ff166f44ffc5fe84f57b024122 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -274,8 +274,8 @@ LocalDOMWindow::LocalDOMWindow(LocalFrame& frame)
     : m_frame(&frame),
       m_visualViewport(DOMVisualViewport::create(this)),
       m_unusedPreloadsTimer(this, &LocalDOMWindow::warnUnusedPreloads),
-      m_shouldPrintWhenFinishedLoading(false) {
-}
+      m_shouldPrintWhenFinishedLoading(false),
+      m_customElements(this, nullptr) {}
 
 void LocalDOMWindow::clearDocument() {
   if (!m_document)
@@ -1565,6 +1565,11 @@ DEFINE_TRACE(LocalDOMWindow) {
   Supplementable<LocalDOMWindow>::trace(visitor);
 }
 
+DEFINE_TRACE_WRAPPERS(LocalDOMWindow) {
+  visitor->traceWrappers(m_customElements);
+  DOMWindow::traceWrappers(visitor);
+}
+
 LocalFrame* LocalDOMWindow::frame() const {
   // If the LocalDOMWindow still has a frame reference, that frame must point
   // back to this LocalDOMWindow: otherwise, it's easy to get into a situation