Disable display item caching

Source/platform/graphics/paint/DisplayItemList.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 DisplayItemList_h
 #define DisplayItemList_h
 
 #include "platform/PlatformExport.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "wtf/HashSet.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class GraphicsContext;
 
 typedef Vector<OwnPtr<DisplayItem>> PaintList;
 
 class PLATFORM_EXPORT DisplayItemList {
     WTF_MAKE_NONCOPYABLE(DisplayItemList);
     WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassOwnPtr<DisplayItemList> create() { return adoptPtr(new DisplayItemList); }
 
+    void beginNewPaints();
+    void endNewPaints();
+
     const PaintList& paintList();
     void add(WTF::PassOwnPtr<DisplayItem>);
 
     void invalidate(DisplayItemClient);
     void invalidateAll();
-    bool clientCacheIsValid(DisplayItemClient client) const { return m_cachedClients.contains(client); }
+    bool clientCacheIsValid(DisplayItemClient) const;
 
     // Plays back the current PaintList() into the given context.
     void replay(GraphicsContext*);
 
 #ifndef NDEBUG
     void showDebugData() const;
 #endif
 
 protected:
-    DisplayItemList() { };
+    DisplayItemList() : m_doingNewPaints(false) { };
 
 private:
     PaintList::iterator findNextMatchingCachedItem(PaintList::iterator, const DisplayItem&);
     bool wasInvalidated(const DisplayItem&) const;
     void updatePaintList();
 
 #ifndef NDEBUG
     WTF::String paintListAsDebugString(const PaintList&) const;
 #endif
 
     PaintList m_paintList;
     HashSet<DisplayItemClient> m_cachedClients;
+    bool m_doingNewPaints;
     PaintList m_newPaints;
 };
 
 } // namespace blink
 
 #endif // DisplayItemList_h