Revert of Move UndoStack from Page to Editor

third_party/WebKit/Source/core/editing/Editor.h

Index: third_party/WebKit/Source/core/editing/Editor.h
diff --git a/third_party/WebKit/Source/core/editing/Editor.h b/third_party/WebKit/Source/core/editing/Editor.h
index 7d21fdde6eecebf6f188497296a65f56423439aa..e2bd766a26d295c6f3010f3a02cfe89e87d24b9d 100644
--- a/third_party/WebKit/Source/core/editing/Editor.h
+++ b/third_party/WebKit/Source/core/editing/Editor.h
@@ -253,7 +253,6 @@
 private:
     Member<LocalFrame> m_frame;
     Member<CompositeEditCommand> m_lastEditCommand;
-    const Member<UndoStack> m_undoStack;
     int m_preventRevealSelection;
     bool m_shouldStartNewKillRingSequence;
     bool m_shouldStyleWithCSS;
@@ -274,6 +273,8 @@
     bool canDeleteRange(const EphemeralRange&) const;
     bool shouldDeleteRange(const EphemeralRange&) const;
 
+    UndoStack* undoStack() const;
+
     bool tryDHTMLCopy();
     bool tryDHTMLCut();
     bool tryDHTMLPaste(PasteMode);