dom.diff

diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -1337,7 +1337,8 @@ Document::Document(const char* aContentT
       mThrowOnDynamicMarkupInsertionCounter(0),
       mIgnoreOpensDuringUnloadCounter(0),
       mDocLWTheme(Doc_Theme_Uninitialized),
-      mSavedResolution(1.0f) {
+      mSavedResolution(1.0f),
+      mPendingInitialTranslation(false) {
   MOZ_LOG(gDocumentLeakPRLog, LogLevel::Debug, ("DOCUMENT %p created", this));
 
   SetIsInDocument();
@@ -3127,6 +3128,9 @@ void Document::LocalizationLinkAdded(Ele
     // will be resolved once the end of l10n resource
     // container is reached.
     mL10nResources.AppendElement(href);
+
+    //printf("In Document::LocalizationLinkAdded, setting mPendingInitialTranslation to true.\n");
+    mPendingInitialTranslation = true;
   }
 }
 
@@ -3174,6 +3178,21 @@ void Document::TriggerInitialDocumentTra
   }
 }
 
+void Document::InitialDocumentTranslationCompleted() {
+  //printf("Document::InitialDocumentTranslationCompleted.\n");
+  mPendingInitialTranslation = false;
+
+  nsCOMPtr<nsIContentSink> sink;
+  if (mParser) {
+    sink = mParser->GetContentSink();
+  } else {
+    sink = do_QueryReferent(mWeakSink);
+  }
+  if (sink) {
+    sink->InitialDocumentTranslationCompleted();
+  }
+}
+
 bool Document::IsWebAnimationsEnabled(JSContext* aCx, JSObject* /*unused*/) {
   MOZ_ASSERT(NS_IsMainThread());
 
@@ -8136,7 +8155,6 @@ void Document::SetReadyStateInternal(Rea
         mXULPersist->Init();
       }
     }
-    TriggerInitialDocumentTranslation();
   }
 
   RecordNavigationTiming(rs);
diff --git a/dom/base/Document.h b/dom/base/Document.h
--- a/dom/base/Document.h
+++ b/dom/base/Document.h
@@ -3394,7 +3394,6 @@ class Document : public nsINode,
    */
   void LocalizationLinkRemoved(Element* aLinkElement);
 
- protected:
   /**
    * This method should be collect as soon as the
    * parsing of the document is completed.
@@ -3409,6 +3408,9 @@ class Document : public nsINode,
    */
   void TriggerInitialDocumentTranslation();
 
+  virtual void InitialDocumentTranslationCompleted();
+
+ protected:
   RefPtr<mozilla::dom::DocumentL10n> mDocumentL10n;
 
  private:
@@ -4440,9 +4442,13 @@ class Document : public nsINode,
   // Pres shell resolution saved before entering fullscreen mode.
   float mSavedResolution;
 
+  bool mPendingInitialTranslation;
+
  public:
   // Needs to be public because the bindings code pokes at it.
   js::ExpandoAndGeneration mExpandoAndGeneration;
+
+  bool HasPendingInitialTranslation() { return mPendingInitialTranslation; }
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(Document, NS_IDOCUMENT_IID)
diff --git a/dom/base/nsContentSink.cpp b/dom/base/nsContentSink.cpp
--- a/dom/base/nsContentSink.cpp
+++ b/dom/base/nsContentSink.cpp
@@ -1170,8 +1170,10 @@ void nsContentSink::StartLayout(bool aIg
 
   mDeferredLayoutStart = true;
 
-  if (!aIgnorePendingSheets && WaitForPendingSheets()) {
-    // Bail out; we'll start layout when the sheets load
+  if (!aIgnorePendingSheets && 
+      (WaitForPendingSheets() ||
+       mDocument->HasPendingInitialTranslation())) {
+    // Bail out; we'll start layout when the sheets and l10n load
     return;
   }
 
diff --git a/dom/xml/nsXMLContentSink.cpp b/dom/xml/nsXMLContentSink.cpp
--- a/dom/xml/nsXMLContentSink.cpp
+++ b/dom/xml/nsXMLContentSink.cpp
@@ -1073,6 +1073,8 @@ nsresult nsXMLContentSink::HandleEndElem
     // probably need to deal here.... (and stop appending them on open).
     mState = eXMLContentSinkState_InEpilog;
 
+    mDocument->TriggerInitialDocumentTranslation();
+
     // We might have had no occasion to start layout yet.  Do so now.
     MaybeStartLayout(false);
   }
@@ -1407,6 +1409,10 @@ nsresult nsXMLContentSink::AddText(const
   return NS_OK;
 }
 
+void nsXMLContentSink::InitialDocumentTranslationCompleted() {
+  StartLayout(false);
+}
+
 void nsXMLContentSink::FlushPendingNotifications(FlushType aType) {
   // Only flush tags if we're not doing the notification ourselves
   // (since we aren't reentrant)
diff --git a/dom/xml/nsXMLContentSink.h b/dom/xml/nsXMLContentSink.h
--- a/dom/xml/nsXMLContentSink.h
+++ b/dom/xml/nsXMLContentSink.h
@@ -67,6 +67,7 @@ class nsXMLContentSink : public nsConten
   NS_IMETHOD WillInterrupt(void) override;
   NS_IMETHOD WillResume(void) override;
   NS_IMETHOD SetParser(nsParserBase* aParser) override;
+  virtual void InitialDocumentTranslationCompleted() override;
   virtual void FlushPendingNotifications(mozilla::FlushType aType) override;
   virtual void SetDocumentCharset(NotNull<const Encoding*> aEncoding) override;
   virtual nsISupports* GetTarget() override;
diff --git a/dom/xul/XULDocument.cpp b/dom/xul/XULDocument.cpp
--- a/dom/xul/XULDocument.cpp
+++ b/dom/xul/XULDocument.cpp
@@ -449,6 +449,12 @@ void XULDocument::AddElementToDocumentPo
   }
 }
 
+void XULDocument::InitialDocumentTranslationCompleted() {
+  //printf("XULDocument::InitialDocumentTranslationCompleted.\n");
+  mPendingInitialTranslation = false;
+  DoneWalking();
+}
+
 void XULDocument::AddSubtreeToDocument(nsIContent* aContent) {
   MOZ_ASSERT(aContent->GetComposedDoc() == this, "Element not in doc!");
 
@@ -971,7 +977,17 @@ nsresult XULDocument::DoneWalking() {
   // XXXldb This is where we should really be setting the chromehidden
   // attribute.
 
+
   if (!mDocumentLoaded) {
+    //printf("In XULDocument::DoneWalking.\n");
+    if (mPendingInitialTranslation) {
+      //printf("Document::mPendingInitialTranslation is true.\n");
+      TriggerInitialDocumentTranslation();
+      return NS_OK;
+    } else {
+      //printf("Document::mPendingInitialTranslation is false.\n");
+    }
+
     // Make sure we don't reenter here from StartLayout().  Note that
     // setting mDocumentLoaded to true here means that if StartLayout()
     // causes ResumeWalk() to be reentered, we'll take the other branch of
@@ -983,18 +999,10 @@ nsresult XULDocument::DoneWalking() {
 
     NotifyPossibleTitleChange(false);
 
-    // For performance reasons, we want to trigger the DocumentL10n's
-    // `TriggerInitialDocumentTranslation` within the same microtask that will
-    // be created for a `MozBeforeInitialXULLayout` event listener.
-    AddEventListener(NS_LITERAL_STRING("MozBeforeInitialXULLayout"),
-                     mDocumentL10n, true, false);
-
     nsContentUtils::DispatchTrustedEvent(
         this, ToSupports(this), NS_LITERAL_STRING("MozBeforeInitialXULLayout"),
         CanBubble::eYes, Cancelable::eNo);
 
-    RemoveEventListener(NS_LITERAL_STRING("MozBeforeInitialXULLayout"),
-                        mDocumentL10n, true);
 
     // Before starting layout, check whether we're a toplevel chrome
     // window.  If we are, setup some state so that we don't have to restyle
diff --git a/dom/xul/XULDocument.h b/dom/xul/XULDocument.h
--- a/dom/xul/XULDocument.h
+++ b/dom/xul/XULDocument.h
@@ -76,6 +76,8 @@ class XULDocument final : public XMLDocu
 
   virtual void EndLoad() override;
 
+  virtual void InitialDocumentTranslationCompleted() override;
+
   // nsIMutationObserver interface
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
diff --git a/intl/l10n/DocumentL10n.cpp b/intl/l10n/DocumentL10n.cpp
--- a/intl/l10n/DocumentL10n.cpp
+++ b/intl/l10n/DocumentL10n.cpp
@@ -312,13 +312,16 @@ class L10nReadyHandler final : public Pr
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(L10nReadyHandler)
 
-  explicit L10nReadyHandler(Promise* aPromise) : mPromise(aPromise) {}
+  explicit L10nReadyHandler(Promise* aPromise, Document* aDocument)
+      : mPromise(aPromise), mDocument(aDocument) {}
 
   void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override {
+    mDocument->InitialDocumentTranslationCompleted();
     mPromise->MaybeResolveWithUndefined();
   }
 
   void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override {
+    mDocument->InitialDocumentTranslationCompleted();
     mPromise->MaybeRejectWithUndefined();
   }
 
@@ -326,6 +329,7 @@ class L10nReadyHandler final : public Pr
   ~L10nReadyHandler() = default;
 
   RefPtr<Promise> mPromise;
+  RefPtr<Document> mDocument;
 };
 
 NS_IMPL_CYCLE_COLLECTION(L10nReadyHandler, mPromise)
@@ -351,7 +355,8 @@ void DocumentL10n::TriggerInitialDocumen
 
   RefPtr<Promise> promise;
   mDOMLocalization->TranslateRoots(getter_AddRefs(promise));
-  RefPtr<PromiseNativeHandler> l10nReadyHandler = new L10nReadyHandler(mReady);
+  RefPtr<PromiseNativeHandler> l10nReadyHandler =
+      new L10nReadyHandler(mReady, mDocument);
   promise->AppendNativeHandler(l10nReadyHandler);
 }
 
diff --git a/parser/html/nsHtml5TreeOpExecutor.cpp b/parser/html/nsHtml5TreeOpExecutor.cpp
--- a/parser/html/nsHtml5TreeOpExecutor.cpp
+++ b/parser/html/nsHtml5TreeOpExecutor.cpp
@@ -170,6 +170,7 @@ nsHtml5TreeOpExecutor::DidBuildModel(boo
     }
 
     if (!destroying) {
+      mDocument->TriggerInitialDocumentTranslation();
       nsContentSink::StartLayout(false);
     }
   }
@@ -228,6 +229,10 @@ nsHtml5TreeOpExecutor::SetParser(nsParse
   return NS_OK;
 }
 
+void nsHtml5TreeOpExecutor::InitialDocumentTranslationCompleted() {
+  nsContentSink::StartLayout(false);
+}
+
 void nsHtml5TreeOpExecutor::FlushPendingNotifications(FlushType aType) {
   if (aType >= FlushType::EnsurePresShellInitAndFrames) {
     // Bug 577508 / 253951
diff --git a/parser/html/nsHtml5TreeOpExecutor.h b/parser/html/nsHtml5TreeOpExecutor.h
--- a/parser/html/nsHtml5TreeOpExecutor.h
+++ b/parser/html/nsHtml5TreeOpExecutor.h
@@ -136,6 +136,8 @@ class nsHtml5TreeOpExecutor final
    */
   NS_IMETHOD WillResume() override;
 
+  virtual void InitialDocumentTranslationCompleted() override;
+
   /**
    * Sets the parser.
    */
diff --git a/parser/htmlparser/nsIContentSink.h b/parser/htmlparser/nsIContentSink.h
--- a/parser/htmlparser/nsIContentSink.h
+++ b/parser/htmlparser/nsIContentSink.h
@@ -130,6 +130,8 @@ class nsIContentSink : public nsISupport
    * Posts a runnable that continues parsing.
    */
   virtual void ContinueInterruptedParsingAsync() {}
+
+  virtual void InitialDocumentTranslationCompleted() {}
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsIContentSink, NS_ICONTENT_SINK_IID)