Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/FixedPositionContainerDisplayItem.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "platform/graphics/paint/FixedPositionContainerDisplayItem.h"
 
 #include "platform/graphics/GraphicsContext.h"
+#include "platform/graphics/paint/DisplayItems.h"
 #include "platform/transforms/AffineTransform.h"
 #include "public/platform/WebDisplayItemList.h"
 
 namespace blink {
 
 void BeginFixedPositionContainerDisplayItem::appendToWebDisplayItemList(WebDisplayItemList* list) const
 {
     // TODO(trchen): Should implement the compositor counterpart and update transform tree algorithm.
 }
 
+void BeginFixedPositionContainerDisplayItem::appendByMoving(DisplayItems& destination)
+{
+    destination.emplaceBack<BeginFixedPositionContainerDisplayItem>(
+        DisplayItemClientWrapperHelper(*this));
+}
+
 void EndFixedPositionContainerDisplayItem::appendToWebDisplayItemList(WebDisplayItemList* list) const
 {
     // TODO(trchen): Should implement the compositor counterpart and update transform tree algorithm.
 }
 
+void EndFixedPositionContainerDisplayItem::appendByMoving(DisplayItems& destination)
+{
+    destination.emplaceBack<EndFixedPositionContainerDisplayItem>(
+        DisplayItemClientWrapperHelper(*this));
+}
+
 } // namespace blink