Simplify RenderLayer::setParent

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index 4196e8f2d9be9e192569aae086b6dfd4f7c80259..922e1a0ac76c8457a90283c6a378e9e52580d84b 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -1404,7 +1404,7 @@ void RenderLayer::addChild(RenderLayer* child, RenderLayer* beforeChild)
     } else
         setLastChild(child);
 
-    child->setParent(this);
+    child->m_parent = this;
 
     setNeedsToUpdateAncestorDependentProperties();
 
@@ -1475,7 +1475,7 @@ RenderLayer* RenderLayer::removeChild(RenderLayer* oldChild)
 
     oldChild->setPreviousSibling(0);
     oldChild->setNextSibling(0);
-    oldChild->setParent(0);
+    oldChild->m_parent = 0;
 
     oldChild->updateDescendantDependentFlags();
     if (subtreeContainsOutOfFlowPositionedLayer(oldChild)) {
@@ -3612,20 +3612,6 @@ bool RenderLayer::childBackgroundIsKnownToBeOpaqueInRect(const LayoutRect& local
     return false;
 }
 
-void RenderLayer::setParent(RenderLayer* parent)
-{
-    if (parent == m_parent)
-        return;
-
-    if (m_parent && !renderer()->documentBeingDestroyed())
-        compositor()->layerWillBeRemoved(m_parent, this);
-
-    m_parent = parent;
-
-    if (m_parent && !renderer()->documentBeingDestroyed())
-        compositor()->layerWasAdded(m_parent, this);
-}
-
 bool RenderLayer::shouldBeSelfPaintingLayer() const
 {
     return m_layerType == NormalLayer