Bug 1625789, optimize CustomElement constructors out from cycle collection graph, r=mccr8

Using the method name GetExistingCustomElements() to match CustomElements(), even though
they both return CustomElementRegistry.

Differential Revision: https://phabricator.services.mozilla.com/D69853

--HG--
extra : moz-landing-system : lando

dom/base/CustomElementRegistry.cpp

@@ -1244,6 +1244,15 @@ already_AddRefed<nsISupports> CustomElementRegistry::CallGetCustomInterface(
   return wrapper.forget();
 }
 
+void CustomElementRegistry::TraceDefinitions(JSTracer* aTrc) {
+  for (auto iter = mCustomDefinitions.Iter(); !iter.Done(); iter.Next()) {
+    RefPtr<CustomElementDefinition>& definition = iter.Data();
+    if (definition && definition->mConstructor) {
+      mozilla::TraceScriptHolder(definition->mConstructor, aTrc);
+    }
+  }
+}
+
 //-----------------------------------------------------
 // CustomElementReactionsStack
 

dom/base/CustomElementRegistry.h

@@ -466,6 +466,8 @@ class CustomElementRegistry final : public nsISupports, public nsWrapperCache {
     elements->PutEntry(elem);
   }
 
+  void TraceDefinitions(JSTracer* aTrc);
+
  private:
   ~CustomElementRegistry();
 

dom/base/nsCCUncollectableMarker.cpp

@@ -31,6 +31,7 @@
 #include "mozilla/dom/ChromeMessageBroadcaster.h"
 #include "mozilla/dom/ContentFrameMessageManager.h"
 #include "mozilla/dom/ContentProcessMessageManager.h"
+#include "mozilla/dom/CustomElementRegistry.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/ParentProcessMessageManager.h"
 #include "mozilla/dom/BrowserChild.h"
@@ -467,6 +468,10 @@ void mozilla::dom::TraceBlackJS(JSTracer* aTrc, bool aIsShutdownGC) {
             if (elm) {
               elm->TraceListeners(aTrc);
             }
+            CustomElementRegistry* cer = inner->GetExistingCustomElements();
+            if (cer) {
+              cer->TraceDefinitions(aTrc);
+            }
           }
         }
 

dom/base/nsGlobalWindowInner.cpp

@@ -2163,6 +2163,10 @@ CustomElementRegistry* nsGlobalWindowInner::CustomElements() {
   return mCustomElements;
 }
 
+CustomElementRegistry* nsGlobalWindowInner::GetExistingCustomElements() {
+  return mCustomElements;
+}
+
 Performance* nsPIDOMWindowInner::GetPerformance() {
   CreatePerformanceObjectIfNeeded();
   return mPerformance;

dom/base/nsGlobalWindowInner.h

@@ -587,6 +587,7 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   mozilla::dom::Location* Location() override;
   nsHistory* GetHistory(mozilla::ErrorResult& aError);
   mozilla::dom::CustomElementRegistry* CustomElements() override;
+  mozilla::dom::CustomElementRegistry* GetExistingCustomElements();
   mozilla::dom::BarProp* GetLocationbar(mozilla::ErrorResult& aError);
   mozilla::dom::BarProp* GetMenubar(mozilla::ErrorResult& aError);
   mozilla::dom::BarProp* GetPersonalbar(mozilla::ErrorResult& aError);