Removing a RenderLayer's CLM should trigger a repaint

Source/core/rendering/compositing/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 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 462 matching lines @@
         layer->setViewportConstrainedNotCompositedReason(viewportConstrainedNotCompositedReason);
         return true;
     }
     return false;
 }
 
 // These are temporary hacks to work around chicken-egg issues while we continue to refactor the compositing code.
 // See crbug.com/383191 for a list of tests that fail if this method is removed.
 void RenderLayerCompositor::applyUpdateLayerCompositingStateChickenEggHacks(RenderLayer* layer, CompositingStateTransitionType compositedLayerUpdate)
 {
-    if (compositedLayerUpdate != NoCompositingStateChange)
-        allocateOrClearCompositedLayerMapping(layer, compositedLayerUpdate);
+    if (compositedLayerUpdate != NoCompositingStateChange) {
+        bool compositedLayerMappingChanged = allocateOrClearCompositedLayerMapping(layer, compositedLayerUpdate);
+        if (compositedLayerMappingChanged) {
+            // Repaint rects can only be computed for layers that have already been attached to the
+            // render tree, but a chicken-egg compositing update can happen before |layer| gets
+            // attached. Since newly-created renderers don't get parented until they are attached
+            // (see RenderTreeBuilder::createRendererForElementIfNeeded), we can check for attachment
+            // by checking for a parent.
+            if (layer->parent())
+                layer->repainter().computeRepaintRectsIncludingNonCompositingDescendants();
+            repaintOnCompositingChange(layer);
+        }
+    }
 }
 
 void RenderLayerCompositor::updateLayerCompositingState(RenderLayer* layer, UpdateLayerCompositingStateOptions options)
 {
     updateDirectCompositingReasons(layer);
     CompositingStateTransitionType compositedLayerUpdate = CompositingLayerAssigner(this).computeCompositedLayerUpdate(layer);
 
     if (compositedLayerUpdate != NoCompositingStateChange)
         setNeedsCompositingUpdate(CompositingUpdateRebuildTree);
 
@@ skipping 744 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "LocalFrame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore