Bug 1718815 - part 3: Move `EditorBase::AutoTransactionBatch` to `HTMLEditor` r=m_kato

I guess that this class is replaced with `AutoPlaceholderBatch`, and both of
them are followed by its instances.  However, I don't want to change the
behavior in this bug.  Therefore, this patch just moves it into `HTMLEditor`.

Depends on D119002

Differential Revision: https://phabricator.services.mozilla.com/D119003

editor/libeditor/EditorBase.h

@@ -60,7 +60,6 @@ namespace mozilla {
 class AlignStateAtSelection;
 class AutoRangeArray;
 class AutoTopLevelEditSubActionNotifier;
-class AutoTransactionBatch;
 class AutoTransactionsConserveSelection;
 class AutoUpdateViewBatch;
 class ChangeAttributeTransaction;
@@ -2147,9 +2146,10 @@ class EditorBase : public nsIEditor,
   MOZ_CAN_RUN_SCRIPT void EndUpdateViewBatch();
 
   /**
-   * Used by AutoTransactionBatch.  After calling BeginTransactionInternal(),
-   * all transactions will be treated as an atomic transaction.  I.e.,
-   * two or more transactions are undid once.
+   * Used by HTMLEditor::AutoTransactionBatch, nsIEditor::BeginTransaction
+   * and nsIEditor::EndTransation.  After calling BeginTransactionInternal(),
+   * all transactions will be treated as an atomic transaction.  I.e., two or
+   * more transactions are undid once.
    * XXX What's the difference with PlaceholderTransaction? Should we always
    *     use it instead?
    */
@@ -2606,28 +2606,6 @@ class EditorBase : public nsIEditor,
   nsresult SetTextDirectionTo(TextDirection aTextDirection);
 
  protected:  // helper classes which may be used by friends
-  /**
-   * Stack based helper class for calling EditorBase::EndTransactionInternal().
-   * NOTE:  This does not suppress multiple input events.  In most cases,
-   *        only one "input" event should be fired for an edit action rather
-   *        than per edit sub-action.  In such case, you should use
-   *        AutoPlaceholderBatch instead.
-   */
-  class MOZ_RAII AutoTransactionBatch final {
-   public:
-    MOZ_CAN_RUN_SCRIPT explicit AutoTransactionBatch(EditorBase& aEditorBase)
-        : mEditorBase(aEditorBase) {
-      MOZ_KnownLive(mEditorBase).BeginTransactionInternal();
-    }
-
-    MOZ_CAN_RUN_SCRIPT ~AutoTransactionBatch() {
-      MOZ_KnownLive(mEditorBase).EndTransactionInternal();
-    }
-
-   protected:
-    EditorBase& mEditorBase;
-  };
-
   /**
    * Stack based helper class for batching a collection of transactions inside
    * a placeholder transaction.  Different from AutoTransactionBatch, this

editor/libeditor/HTMLEditor.h

@@ -4407,6 +4407,29 @@ class HTMLEditor final : public EditorBase,
     MOZ_KNOWN_LIVE HTMLEditor* mHTMLEditor = nullptr;
   };
 
+  /**
+   * Stack based helper class for calling EditorBase::EndTransactionInternal().
+   * NOTE:  This does not suppress multiple input events.  In most cases,
+   *        only one "input" event should be fired for an edit action rather
+   *        than per edit sub-action.  In such case, you should use
+   *        EditorBase::AutoPlaceholderBatch instead.
+   */
+  class MOZ_RAII AutoTransactionBatch final {
+   public:
+    MOZ_CAN_RUN_SCRIPT explicit AutoTransactionBatch(HTMLEditor& aHTMLEditor)
+        : mHTMLEditor(aHTMLEditor) {
+      MOZ_KnownLive(mHTMLEditor).BeginTransactionInternal();
+    }
+
+    MOZ_CAN_RUN_SCRIPT ~AutoTransactionBatch() {
+      MOZ_KnownLive(mHTMLEditor).EndTransactionInternal();
+    }
+
+   protected:
+    // The lifetime must be guaranteed by the creator of this instance.
+    MOZ_KNOWN_LIVE HTMLEditor& mHTMLEditor;
+  };
+
   RefPtr<TypeInState> mTypeInState;
   RefPtr<ComposerCommandsUpdater> mComposerCommandsUpdater;