Make DisplayItem::replay const.

third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp

 // Copyright 2014 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/DisplayItemList.h"
 
 #include "platform/NotImplemented.h"
 #include "platform/TraceEvent.h"
 #include "platform/graphics/GraphicsLayer.h"
@@ skipping 559 matching lines @@
 }
 
 void DisplayItemList::showDebugData() const
 {
     WTFLogAlways("current display items: [%s]\n", displayItemsAsDebugString(m_currentDisplayItems).utf8().data());
     WTFLogAlways("new display items: [%s]\n", displayItemsAsDebugString(m_newDisplayItems).utf8().data());
 }
 
 #endif // ifndef NDEBUG
 
-void DisplayItemList::replay(GraphicsContext& context)
+void DisplayItemList::replay(GraphicsContext& context) const
 {
     TRACE_EVENT0("blink,benchmark", "DisplayItemList::replay");
     ASSERT(m_newDisplayItems.isEmpty());
-    for (DisplayItem& displayItem : m_currentDisplayItems)
+    for (const DisplayItem& displayItem : m_currentDisplayItems)
         displayItem.replay(context);
 }
 
 } // namespace blink