Revert of Move UndoStack from Page to Editor

third_party/WebKit/Source/core/page/Page.cpp

Index: third_party/WebKit/Source/core/page/Page.cpp
diff --git a/third_party/WebKit/Source/core/page/Page.cpp b/third_party/WebKit/Source/core/page/Page.cpp
index ff71fae0c65ade2aa799053f8718ba2b8a3e55f3..270e298c1c35d0db22488e97117b180cc0310be5 100644
--- a/third_party/WebKit/Source/core/page/Page.cpp
+++ b/third_party/WebKit/Source/core/page/Page.cpp
@@ -24,6 +24,7 @@
 #include "core/dom/StyleChangeReason.h"
 #include "core/dom/VisitedLinkState.h"
 #include "core/editing/DragCaretController.h"
+#include "core/editing/commands/UndoStack.h"
 #include "core/editing/markers/DocumentMarkerController.h"
 #include "core/events/Event.h"
 #include "core/fetch/ResourceFetcher.h"
@@ -115,6 +116,7 @@
     , m_focusController(FocusController::create(this))
     , m_contextMenuController(ContextMenuController::create(this, pageClients.contextMenuClient))
     , m_pointerLockController(PointerLockController::create(this))
+    , m_undoStack(UndoStack::create())
     , m_mainFrame(nullptr)
     , m_editorClient(pageClients.editorClient)
     , m_spellCheckerClient(pageClients.spellCheckerClient)
@@ -472,6 +474,7 @@
     visitor->trace(m_contextMenuController);
     visitor->trace(m_pointerLockController);
     visitor->trace(m_scrollingCoordinator);
+    visitor->trace(m_undoStack);
     visitor->trace(m_mainFrame);
     visitor->trace(m_validationMessageClient);
     visitor->trace(m_frameHost);