Clear the groupedMapping parameter in layers when removed from the group

Source/core/layout/compositing/CompositedDeprecatedPaintLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 167 matching lines @@
 
 CompositedDeprecatedPaintLayerMapping::~CompositedDeprecatedPaintLayerMapping()
 {
     // Hits in compositing/squashing/squash-onto-nephew.html.
     DisableCompositingQueryAsserts disabler;
 
     // Do not leave the destroyed pointer dangling on any Layers that painted to this mapping's squashing layer.
     for (size_t i = 0; i < m_squashedLayers.size(); ++i) {
         DeprecatedPaintLayer* oldSquashedLayer = m_squashedLayers[i].paintLayer;
         if (oldSquashedLayer->groupedMapping() == this) {
-            oldSquashedLayer->setGroupedMapping(0, true);
+            oldSquashedLayer->setGroupedMapping(0, DeprecatedPaintLayer::DoNotInvalidateLayerAndRemoveFromMapping);
             oldSquashedLayer->setLostGroupedMapping(true);
         }
     }
 
     updateClippingLayers(false, false);
     updateOverflowControlsLayers(false, false, false, false);
     updateChildTransformLayer(false);
     updateForegroundLayer(false);
     updateBackgroundLayer(false);
     updateMaskLayer(false);
@@ skipping 2061 matching lines @@
 
 bool CompositedDeprecatedPaintLayerMapping::updateSquashingLayerAssignment(DeprecatedPaintLayer* squashedLayer, const DeprecatedPaintLayer& owningLayer, size_t nextSquashedLayerIndex)
 {
     GraphicsLayerPaintInfo paintInfo;
     paintInfo.paintLayer = squashedLayer;
     // NOTE: composited bounds are updated elsewhere
     // NOTE: offsetFromLayoutObject is updated elsewhere
 
     // Change tracking on squashing layers: at the first sign of something changed, just invalidate the layer.
     // FIXME: Perhaps we can find a tighter more clever mechanism later.
-    bool updatedAssignment = false;
     if (nextSquashedLayerIndex < m_squashedLayers.size()) {
-        if (paintInfo.paintLayer != m_squashedLayers[nextSquashedLayerIndex].paintLayer) {
-            compositor()->paintInvalidationOnCompositingChange(squashedLayer);
-            updatedAssignment = true;
-            m_squashedLayers[nextSquashedLayerIndex] = paintInfo;
-        }
+        if (paintInfo.paintLayer == m_squashedLayers[nextSquashedLayerIndex].paintLayer)
+            return false;
+
+        // Must invalidate before adding the squashed layer to the mapping.
+        compositor()->paintInvalidationOnCompositingChange(squashedLayer);
+
+        // Clear pointer on the previous entry.
+        m_squashedLayers[nextSquashedLayerIndex].paintLayer->setGroupedMapping(nullptr, DeprecatedPaintLayer::DoNotInvalidateLayerAndRemoveFromMapping);
+        m_squashedLayers[nextSquashedLayerIndex] = paintInfo;
     } else {
+        // Must invalidate before adding the squashed layer to the mapping.
         compositor()->paintInvalidationOnCompositingChange(squashedLayer);
         m_squashedLayers.append(paintInfo);
-        updatedAssignment = true;
     }
-    squashedLayer->setGroupedMapping(this);
-    return updatedAssignment;
+    squashedLayer->setGroupedMapping(this, DeprecatedPaintLayer::InvalidateLayerAndRemoveFromMapping);
+
+    return true;
 }
 
 void CompositedDeprecatedPaintLayerMapping::removeLayerFromSquashingGraphicsLayer(const DeprecatedPaintLayer* layer)
 {
-    size_t layerIndex = kNotFound;
+    size_t layerIndex = 0;
+    for (; layerIndex < m_squashedLayers.size(); ++layerIndex)
+        if (m_squashedLayers[layerIndex].paintLayer == layer)
+            break;
 
-    for (size_t i = 0; i < m_squashedLayers.size(); ++i) {
-        if (m_squashedLayers[i].paintLayer == layer) {
-            layerIndex = i;
-            break;
-        }
-    }
-
-    if (layerIndex == kNotFound)
+    if (layerIndex == m_squashedLayers.size())
         return;
 
     m_squashedLayers.remove(layerIndex);
 }
 
 void CompositedDeprecatedPaintLayerMapping::finishAccumulatingSquashingLayers(size_t nextSquashedLayerIndex)
 {
-    // Any additional squashed Layers in the array no longer exist, and removing invalidates the squashingLayer contents.
-    if (nextSquashedLayerIndex < m_squashedLayers.size())
+    // Any additional squashed Layers in the array no longer exist, and removing invalidates the
+    // squashingLayer contents.
+    if (nextSquashedLayerIndex < m_squashedLayers.size()) {
+        for (size_t i = m_squashedLayers.size(); i > nextSquashedLayerIndex; --i)
+            m_squashedLayers[i-1].paintLayer->setGroupedMapping(nullptr, DeprecatedPaintLayer::DoNotInvalidateLayerAndRemoveFromMapping);
         m_squashedLayers.remove(nextSquashedLayerIndex, m_squashedLayers.size() - nextSquashedLayerIndex);
+    }
 }
 
 String CompositedDeprecatedPaintLayerMapping::debugName(const GraphicsLayer* graphicsLayer)
 {
     String name;
     if (graphicsLayer == m_graphicsLayer.get()) {
         name = m_owningLayer.debugName();
     } else if (graphicsLayer == m_squashingContainmentLayer.get()) {
         name = "Squashing Containment Layer";
     } else if (graphicsLayer == m_squashingLayer.get()) {
@@ skipping 29 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink