Set geometry dirty bits on composited layer mappings when updating squashed layers.

Source/core/rendering/compositing/RenderLayerCompositor.cpp

Index: Source/core/rendering/compositing/RenderLayerCompositor.cpp
diff --git a/Source/core/rendering/compositing/RenderLayerCompositor.cpp b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
index 4aa993786998fa87c6b571a548360a1107fd89a6..c1fb21fe8ee13131a68a5c63f4710b3832ddc1b8 100644
--- a/Source/core/rendering/compositing/RenderLayerCompositor.cpp
+++ b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
@@ -695,6 +695,8 @@ bool RenderLayerCompositor::updateSquashingAssignment(RenderLayer* layer, Squash
 
         return true;
     } else if (compositedLayerUpdate == RemoveFromSquashingLayer) {
+        if (layer->groupedMapping())
+            layer->groupedMapping()->setNeedsGeometryUpdate();
         layer->setGroupedMapping(0);

[abarth-chromium, 2014/03/17 17:17:03]

Maybe this call to setNeedsGeometryUpdate should happen inside
setGroupedMapping.  Presumably every caller of setGroupedMapping needs this as
well.

[chrishtr, 2014/03/17 18:10:55]

Done.

 
         // This layer and all of its descendants have cached repaints rects that are relative to