Remove the HashMap in RenderLayerCompositor's overlap map

Source/core/rendering/compositing/RenderLayerCompositor.h

Index: Source/core/rendering/compositing/RenderLayerCompositor.h
diff --git a/Source/core/rendering/compositing/RenderLayerCompositor.h b/Source/core/rendering/compositing/RenderLayerCompositor.h
index 117c752234b77d29779ddc25da5e1b3f58060be4..4ecddf85ad84b78ceb5c0cdd90564200ca6bdab2 100644
--- a/Source/core/rendering/compositing/RenderLayerCompositor.h
+++ b/Source/core/rendering/compositing/RenderLayerCompositor.h
@@ -262,15 +262,13 @@ private:
 
     void recursiveRepaintLayer(RenderLayer*);
 
-    void addToOverlapMap(OverlapMap&, RenderLayer*, IntRect& layerBounds, bool& boundsComputed);
-    void addToOverlapMapRecursive(OverlapMap&, RenderLayer*, RenderLayer* ancestorLayer = 0);
+    void addToOverlapMap(OverlapMap&, RenderLayer*, IntRect& layerBounds);
 
     // Forces an update for all frames of frame tree recursively. Used only when the mainFrame compositor is ready to
     // finish all deferred work.
     static void finishCompositingUpdateForFrameTree(LocalFrame*);
 
-    // Returns true if any layer's compositing changed
-    void computeCompositingRequirements(RenderLayer* ancestorLayer, RenderLayer*, OverlapMap*, struct CompositingRecursionData&, bool& descendantHas3DTransform, Vector<RenderLayer*>& unclippedDescendants);
+    void computeCompositingRequirements(RenderLayer* ancestorLayer, RenderLayer*, OverlapMap*, struct CompositingRecursionData&, bool& descendantHas3DTransform, Vector<RenderLayer*>& unclippedDescendants, IntRect& absoluteDecendantBoundingBox);
 
     // Defines which RenderLayers will paint into which composited backings, by allocating and destroying CompositedLayerMappings as needed.
     void assignLayersToBackings(RenderLayer*, bool& layersChanged);