[Editing] Introduce |EditCommandComposition::willUn/Reapply()| in prepare for 'beforeinput' (2/3)

third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.h

Index: third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.h
diff --git a/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.h b/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.h
index 54ca077d5db6597c4bd1d754a03742399a707923..39ffedf1bb80c08f6a62ab4ebd3e10edd2c36d17 100644
--- a/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.h
+++ b/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.h
@@ -52,8 +52,8 @@ class EditCommandComposition final : public UndoStep {
                                         InputEvent::InputType);
 
   bool belongsTo(const LocalFrame&) const override;
-  void unapply() override;
-  void reapply() override;
+  void unapply(EditCommandSource) override;
+  void reapply(EditCommandSource) override;
   InputEvent::InputType inputType() const override;
   void append(SimpleEditCommand*);
   void append(EditCommandComposition*);
@@ -79,6 +79,14 @@ class EditCommandComposition final : public UndoStep {
                          const VisibleSelection& endingSelection,
                          InputEvent::InputType);
 
+  // TODO(chongz): Implement "beforeinput" as described below:
+  // Fires "beforeinput" and will returns |false| to cancel unapply / reapply if
+  //   * "beforeinput" was canceled, or
+  //   * |frame| was destroyed by event handlers.
+  // Note: Undo stack will always get popped.
+  bool willUnapply(EditCommandSource);
+  bool willReapply(EditCommandSource);
+
   Member<Document> m_document;
   VisibleSelection m_startingSelection;
   VisibleSelection m_endingSelection;