Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/DisplayItem.cpp

Index: Source/platform/graphics/paint/DisplayItem.cpp
diff --git a/Source/platform/graphics/paint/DisplayItem.cpp b/Source/platform/graphics/paint/DisplayItem.cpp
index c5ea8215da9c523be93db06cc0d55cc498b57665..c359ed1eaf5396f42097ce063497c61d5026a7d7 100644
--- a/Source/platform/graphics/paint/DisplayItem.cpp
+++ b/Source/platform/graphics/paint/DisplayItem.cpp
@@ -168,6 +168,9 @@ WTF::String DisplayItem::typeAsDebugString(Type type)
     PAINT_PHASE_BASED_DEBUG_STRINGS(BeginSubtree);
     PAINT_PHASE_BASED_DEBUG_STRINGS(EndSubtree);
 
+    if (type == UninitializedType)
+        return "UninitializedType";
+
     switch (type) {
         DEBUG_STRING_CASE(BeginFilter);
         DEBUG_STRING_CASE(EndFilter);