Add DisplayItemList::newDisplayItems() and cleanup tests

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/RuntimeEnabledFeatures.h"
 #include "platform/geometry/LayoutPoint.h"
@@ skipping 116 matching lines @@
         commitNewDisplayItems();
         replay(context);
     }
 
     void appendToWebDisplayItemList(WebDisplayItemList*);
     void commitNewDisplayItemsAndAppendToWebDisplayItemList(WebDisplayItemList*);
 
     bool displayItemConstructionIsDisabled() const { return m_constructionDisabled; }
     void setDisplayItemConstructionIsDisabled(const bool disable) { m_constructionDisabled = disable; }
 
-#if ENABLE(ASSERT)
-    size_t newDisplayItemsSize() const { return m_newDisplayItems.size(); }
-#endif
+    // Returns displayItems added using createAndAppend() since beginning or the last
+    // commitNewDisplayItems(). Use with care.
+    DisplayItems& newDisplayItems() { return m_newDisplayItems; }
 
 #ifndef NDEBUG
     void showDebugData() const;
 #endif
 
     void startTrackingPaintInvalidationObjects()
     {
         ASSERT(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
         m_trackedPaintInvalidationObjects = adoptPtr(new Vector<String>());
     }
@@ skipping 12 matching lines @@
     DisplayItemList()
         : m_currentDisplayItems(0)
         , m_newDisplayItems(kInitialDisplayItemsCapacity * kMaximumDisplayItemSize)
         , m_validlyCachedClientsDirty(false)
         , m_constructionDisabled(false)
         , m_skippingCacheCount(0)
         , m_numCachedItems(0)
         , m_nextScope(1) { }
 
 private:
-    friend class DisplayItemListTest;
-    friend class DisplayItemListPaintTest;
-    friend class DisplayItemListPaintTestForSlimmingPaintV2;
-    friend class LayoutObjectDrawingRecorderTest;
-    friend class LayoutObjectDrawingRecorderTestForSlimmingPaintV2;
-
     // Set new item state (scopes, cache skipping, etc) for a new item.
     void processNewItem(DisplayItem&);
 
     void updateValidlyCachedClientsIfNeeded() const;
 
     // Update the recorded paint offsets to remove any items that no longer have
     // corresponding cached display items.
     // TODO(pdr): Remove this once the paint offset cache is on LayoutObject.
     void removeUnneededPaintOffsetEntries();
 
@@ skipping 62 matching lines @@
     // the duplicated ids are from.
     DisplayItemIndicesByClientMap m_newDisplayItemIndicesByClient;
 #endif
 
     OwnPtr<Vector<String>> m_trackedPaintInvalidationObjects;
 };
 
 } // namespace blink
 
 #endif // DisplayItemList_h