Bug 1819664 - Block onload on pending l10n mutations. r=smaug,Gijs

Remove custom code doing this for <dialog>.

Differential Revision: https://phabricator.services.mozilla.com/D171475

dom/base/Document.h

@@ -3809,11 +3809,9 @@ class Document : public nsINode,
   nsresult Dispatch(TaskCategory aCategory,
                     already_AddRefed<nsIRunnable>&& aRunnable) final;
 
-  virtual nsISerialEventTarget* EventTargetFor(
-      TaskCategory aCategory) const override;
+  nsISerialEventTarget* EventTargetFor(TaskCategory) const override;
 
-  virtual AbstractThread* AbstractMainThreadFor(
-      TaskCategory aCategory) override;
+  AbstractThread* AbstractMainThreadFor(TaskCategory) override;
 
   // The URLs passed to this function should match what
   // JS::DescribeScriptedCaller() returns, since this API is used to

dom/l10n/L10nMutations.cpp

@@ -9,6 +9,7 @@
 #include "nsRefreshDriver.h"
 #include "DOMLocalization.h"
 #include "mozilla/intl/Localization.h"
+#include "nsThreadManager.h"
 
 using namespace mozilla;
 using namespace mozilla::intl;
@@ -132,13 +133,38 @@ void L10nMutations::ContentRemoved(nsIContent* aChild,
 }
 
 void L10nMutations::L10nElementChanged(Element* aElement) {
+  const bool wasEmpty = mPendingElements.IsEmpty();
+
   if (mPendingElementsHash.EnsureInserted(aElement)) {
     mPendingElements.AppendElement(aElement);
   }
 
+  if (!wasEmpty) {
+    return;
+  }
+
   if (!mRefreshDriver) {
     StartRefreshObserver();
   }
+
+  if (!mBlockingLoad) {
+    Document* doc = GetDocument();
+    if (doc && doc->GetReadyStateEnum() != Document::READYSTATE_COMPLETE) {
+      doc->BlockOnload();
+      mBlockingLoad = true;
+      // We want to make sure we flush translations and don't block the load
+      // indefinitely (and, in fact, that we do it rather soon, even if the
+      // refresh driver is not ticking yet).
+      //
+      // In some platforms (mainly Wayland) the load of the main document
+      // causes vsync to start running and start ticking the refresh driver,
+      // so we can't rely on the refresh driver ticking yet.
+      RefPtr<nsIRunnable> task =
+          NewRunnableMethod("FlushPendingTranslationsBeforeLoad", this,
+                            &L10nMutations::FlushPendingTranslations);
+      nsThreadManager::get().DispatchDirectTaskToCurrentThread(task);
+    }
+  }
 }
 
 void L10nMutations::PauseObserving() { mObserving = false; }
@@ -241,9 +267,14 @@ void L10nMutations::MaybeFirePendingTranslationsFinished() {
   }
 
   RefPtr doc = GetDocument();
-  if (!doc) {
+  if (NS_WARN_IF(!doc)) {
     return;
   }
+
+  if (mBlockingLoad) {
+    mBlockingLoad = false;
+    doc->UnblockOnload(false);
+  }
   nsContentUtils::DispatchEventOnlyToChrome(
       doc, ToSupports(doc), u"L10nMutationsFinished"_ns, CanBubble::eNo,
       Cancelable::eNo, Composed::eNo, nullptr);

dom/l10n/L10nMutations.h

@@ -70,6 +70,7 @@ class L10nMutations final : public nsStubMultiMutationObserver,
 
  private:
   bool mObserving = false;
+  bool mBlockingLoad = false;
   uint32_t mPendingPromises = 0;
   RefPtr<nsRefreshDriver> mRefreshDriver;
   DOMLocalization* mDOMLocalization;

security/manager/pki/resources/content/editcacert.js

@@ -14,12 +14,9 @@ var gCertDB = Cc["@mozilla.org/security/x509certdb;1"].getService(
  */
 var gCert = window.arguments[0];
 
-document.mozSubdialogReady = init();
+document.addEventListener("DOMContentLoaded", init);
 
-async function init() {
-  await new Promise(r => {
-    document.addEventListener("DOMContentLoaded", r, { once: true });
-  });
+function init() {
   document.addEventListener("dialogaccept", onDialogAccept);
 
   let sslCheckbox = document.getElementById("trustSSL");
@@ -37,12 +34,9 @@ async function init() {
   );
 
   let certMsg = document.getElementById("certmsg");
-  document.l10n.pauseObserving();
   document.l10n.setAttributes(certMsg, "edit-trust-ca", {
     certName: gCert.commonName,
   });
-  document.l10n.resumeObserving();
-  await document.l10n.translateElements([certMsg]);
 }
 
 /**

toolkit/content/widgets/dialog.js

@@ -14,13 +14,6 @@
   class MozDialog extends MozXULElement {
     constructor() {
       super();
-
-      /**
-       * Gets populated by elements that are passed to document.l10n.setAttributes
-       * to localize the dialog buttons. Needed to properly size the dialog after
-       * the asynchronous translation.
-       */
-      this._l10nButtons = [];
     }
 
     static get observedAttributes() {
@@ -99,6 +92,7 @@
       this.attachShadow({ mode: "open" });
 
       document.documentElement.setAttribute("role", "dialog");
+      document.l10n?.connectRoot(this.shadowRoot);
 
       this.shadowRoot.textContent = "";
       this.shadowRoot.appendChild(
@@ -148,17 +142,6 @@
         }
       });
 
-      if (this._l10nButtons.length) {
-        document.blockUnblockOnload(true);
-        this._translationReady = document.l10n.ready.then(async () => {
-          try {
-            await document.l10n.translateElements(this._l10nButtons);
-          } finally {
-            document.blockUnblockOnload(false);
-          }
-        });
-      }
-
       // Call postLoadInit for things that we need to initialize after onload.
       if (document.readyState == "complete") {
         this._postLoadInit();
@@ -347,13 +330,6 @@
 
     async _postLoadInit() {
       this._setInitialFocusIfNeeded();
-      if (this._translationReady) {
-        await this._translationReady;
-      }
-      if (document.mozSubDialogReady) {
-        await document.mozSubDialogReady;
-      }
-
       let finalStep = () => {
         this._sizeToPreferredSize();
         this._snapCursorToDefaultButtonIfNeeded();
@@ -437,7 +413,6 @@
               button,
               this.getAttribute("buttonid" + dlgtype)
             );
-            this._l10nButtons.push(button);
           } else if (dlgtype != "extra1" && dlgtype != "extra2") {
             button.setAttribute(
               "label",