Create PaintChunk and begin writing code to build paint chunks.

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

Index: third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
index 7b329e4b43742f9a9cdd8e57da2989a2e2763a5b..f10bc01f75120e24477494b827ce34ce7d72b212 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
+++ b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
@@ -23,6 +23,12 @@ const DisplayItems& DisplayItemList::displayItems() const
     return m_currentDisplayItems;
 }
 
+const Vector<PaintChunk>& DisplayItemList::paintChunks() const
+{
+    ASSERT(m_newPaintChunks.isInInitialState());
+    return m_currentPaintChunks;
+}
+
 bool DisplayItemList::lastDisplayItemIsNoopBegin() const
 {
     if (m_newDisplayItems.isEmpty())
@@ -47,6 +53,7 @@ void DisplayItemList::removeLastDisplayItem()
     }
 #endif
     m_newDisplayItems.removeLast();
+    m_newPaintChunks.decrementDisplayItemIndex();
 }
 
 void DisplayItemList::processNewItem(DisplayItem& displayItem)
@@ -84,6 +91,13 @@ void DisplayItemList::processNewItem(DisplayItem& displayItem)
 
     if (skippingCache())
         displayItem.setSkippedCache();
+
+    m_newPaintChunks.incrementDisplayItemIndex();
+}
+
+void DisplayItemList::updateCurrentPaintProperties(const PaintProperties& newPaintProperties)
+{
+    m_newPaintChunks.updateCurrentPaintProperties(newPaintProperties);
 }
 
 void DisplayItemList::beginScope()
@@ -272,6 +286,7 @@ void DisplayItemList::commitNewDisplayItems(DisplayListDiff*)
             ASSERT(!item.isCached());
 #endif
         m_currentDisplayItems.swap(m_newDisplayItems);
+        m_currentPaintChunks = m_newPaintChunks.releasePaintChunks();
         m_validlyCachedClientsDirty = true;
         m_numCachedItems = 0;
         return;
@@ -288,6 +303,7 @@ void DisplayItemList::commitNewDisplayItems(DisplayListDiff*)
 
     // TODO(jbroman): Consider revisiting this heuristic.
     DisplayItems updatedList(std::max(m_currentDisplayItems.usedCapacityInBytes(), m_newDisplayItems.usedCapacityInBytes()));
+    Vector<PaintChunk> updatedPaintChunks;
     DisplayItems::iterator currentIt = m_currentDisplayItems.begin();
     DisplayItems::iterator currentEnd = m_currentDisplayItems.end();
     for (DisplayItems::iterator newIt = m_newDisplayItems.begin(); newIt != m_newDisplayItems.end(); ++newIt) {
@@ -350,6 +366,10 @@ void DisplayItemList::commitNewDisplayItems(DisplayListDiff*)
         checkNoRemainingCachedDisplayItems();
 #endif // ENABLE(ASSERT)
 
+    // TODO(jbroman): When subsequence caching applies to SPv2, we'll need to
+    // merge the paint chunks as well.
+    m_currentPaintChunks = m_newPaintChunks.releasePaintChunks();
+
     m_newDisplayItems.clear();
     m_validlyCachedClientsDirty = true;
     m_currentDisplayItems.swap(updatedList);