Separate display item clients for negative and normal/positive z-order children

third_party/WebKit/Source/core/paint/PaintLayer.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index ded24777fc93352efa5270495cbf6fd8340df234..5c51a6d3dde2368f24f0bcc85884d925625c95db 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -2716,6 +2716,26 @@ void PaintLayer::clearNeedsRepaintRecursively()
     m_needsRepaint = false;
 }
 
+static String debugNameForNegativeZOrderChildrenDisplayItemClient(const PaintLayer& layer)
+{
+    return layer.debugName() + " negative z-order children";
+}
+
+static String debugNameForNormalAndPositiveZOrderChildrenDisplayItemClient(const PaintLayer& layer)
+{
+    return layer.debugName() + " normal and positive z-order children";
+}
+
+DisplayItemClientWrapper PaintLayer::displayItemClientForNegativeZOrderChildren() const
+{
+    return DisplayItemClientWrapper(*this, toSubDisplayItemClient(this, 1), debugNameForNegativeZOrderChildrenDisplayItemClient);
+}
+
+DisplayItemClientWrapper PaintLayer::displayItemClientForNormalAndPositiveZOrderChildren() const
+{
+    return DisplayItemClientWrapper(*this, toSubDisplayItemClient(this, 2), debugNameForNormalAndPositiveZOrderChildrenDisplayItemClient);
+}
+
 DisableCompositingQueryAsserts::DisableCompositingQueryAsserts()
     : m_disabler(gCompositingQueryMode, CompositingQueriesAreAllowed) { }