Slimming Paint phase 2 compositing algorithm plumbing & skeleton display list API.

Source/platform/graphics/paint/DisplayItemList.cpp

Index: Source/platform/graphics/paint/DisplayItemList.cpp
diff --git a/Source/platform/graphics/paint/DisplayItemList.cpp b/Source/platform/graphics/paint/DisplayItemList.cpp
index 4ab57645977aea021603cc6a739c4005d75bf2e0..a8a034449e2865a067aaced84f9286409a2f825c 100644
--- a/Source/platform/graphics/paint/DisplayItemList.cpp
+++ b/Source/platform/graphics/paint/DisplayItemList.cpp
@@ -32,6 +32,19 @@ const DisplayItems& DisplayItemList::displayItems() const
     return m_currentDisplayItems;
 }
 
+const WebVector<WebDisplayItem>& DisplayItemList::webDisplayItems() const
+{
+    return m_webDisplayItems;
+}
+
+const skia::DiscardablePixelRefList& DisplayItemList::pixelRefs() const
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintCompositorLayerizationEnabled());
+    ASSERT(m_newPixelRefs.empty());
+    return m_currentPixelRefs;
+}
+
+
 bool DisplayItemList::lastDisplayItemIsNoopBegin() const
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
@@ -60,6 +73,11 @@ void DisplayItemList::removeLastDisplayItem()
     m_newDisplayItems.removeLast();
 }
 
+void DisplayItemList::addPixelRef(const skia::PixelRefUtils::PositionPixelRef& pixelRef)
+{
+    m_newPixelRefs.push_back(pixelRef);
+}
+
 void DisplayItemList::processNewItem(DisplayItem* displayItem)
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
@@ -216,7 +234,8 @@ DisplayItems::Iterator DisplayItemList::findOutOfOrderCachedItemForward(DisplayI
 // The algorithm is O(|m_currentDisplayItems| + |m_newDisplayItems|).
 // Coefficients are related to the ratio of out-of-order [Subtree]CachedDisplayItems
 // and the average number of (Drawing|BeginSubtree)DisplayItems per client.
-void DisplayItemList::commitNewDisplayItems()
+// TODO(chrishtr); implement filling of displayListDiff.
+void DisplayItemList::commitNewDisplayItems(WebDisplayListDiff* displayListDiff)
 {
     TRACE_EVENT2("blink,benchmark", "DisplayItemList::commitNewDisplayItems", "current_display_list_size", (int)m_currentDisplayItems.size(),
         "num_non_cached_new_items", (int)m_newDisplayItems.size() - m_numCachedItems);
@@ -240,6 +259,7 @@ void DisplayItemList::commitNewDisplayItems()
         m_currentDisplayItems.swap(m_newDisplayItems);
         m_validlyCachedClientsDirty = true;
         m_numCachedItems = 0;
+        m_currentPixelRefs.swap(m_newPixelRefs);
         return;
     }
 
@@ -325,6 +345,7 @@ void DisplayItemList::commitNewDisplayItems()
     m_newDisplayItems.clear();
     m_validlyCachedClientsDirty = true;
     m_currentDisplayItems.swap(updatedList);
+    m_currentPixelRefs.swap(m_newPixelRefs);
     m_numCachedItems = 0;
 }