Make DisplayItem::replay const.

third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h

 // 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.
 
 #ifndef DisplayItem_h
 #define DisplayItem_h
 
 #include "platform/PlatformExport.h"
 #include "platform/graphics/ContiguousContainer.h"
 #include "platform/graphics/paint/DisplayItemClient.h"
@@ skipping 228 matching lines @@
             return cachedSubsequenceTypeToSubsequenceType(type);
         return type;
     }
 
     // Return the Id with cached type converted to non-cached type.
     Id nonCachedId() const
     {
         return Id(m_client, nonCachedType(m_type), m_scope);
     }
 
-    virtual void replay(GraphicsContext&) { }
+    virtual void replay(GraphicsContext&) const { }
 
     DisplayItemClient client() const { return m_client; }
     Type type() const { return m_type; }
 
     void setScope(unsigned scope) { m_scope = scope; }
     unsigned scope() { return m_scope; }
 
     // Size of this object in memory, used to move it with memcpy.
     // This is not sizeof(*this), because it needs to account for the size of
     // the derived class (i.e. runtime type). Derived classes are expected to
@@ skipping 134 matching lines @@
     bool isEndAndPairedWith(DisplayItem::Type otherType) const override = 0;
 #endif
 
 private:
     bool isEnd() const final { return true; }
 };
 
 } // namespace blink
 
 #endif // DisplayItem_h