[RAL] Make sure RenderLayers are invalidated when moved.

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 674186b357cc25273a1c4e223c1de0ad0ca2c62d..3a0f396013cbf34c1079a71d8ae3eb24f96ead11 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -263,10 +263,10 @@ void RenderLayer::updateLayerPositionsAfterLayout(const RenderLayer* rootLayer,
     RenderGeometryMap geometryMap(UseTransforms);
     if (this != rootLayer)
         geometryMap.pushMappingsToAncestor(parent(), 0);
-    updateLayerPositions(&geometryMap, flags);
+    updateLayerPositions(&geometryMap, rootLayer->renderer()->containerForRepaint(), flags);
 }
 
-void RenderLayer::updateLayerPositions(RenderGeometryMap* geometryMap, UpdateLayerPositionsFlags flags)
+void RenderLayer::updateLayerPositions(RenderGeometryMap* geometryMap, const RenderLayerModelObject* paintInvalidationContainer, UpdateLayerPositionsFlags flags)
 {
     updateLayerPosition(); // For relpositioned layers or non-positioned layers,
                            // we need to keep in sync, since we may have shifted relative
@@ -298,6 +298,18 @@ void RenderLayer::updateLayerPositions(RenderGeometryMap* geometryMap, UpdateLay
         m_enclosingPaginationLayer = 0;
     }
 
+    const RenderLayerModelObject* newPaintInvalidationContainer = paintInvalidationContainer;
+    if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
+        bool establishesNewPaintInvalidationContainer = isRepaintContainer();
+        newPaintInvalidationContainer = renderer()->adjustCompositedContainerForSpecialAncestors(establishesNewPaintInvalidationContainer ? renderer() : paintInvalidationContainer);
+
+        if (geometryMap) {
+            LayoutPoint offset = renderer()->isBox() ? toRenderBox(renderer())->location() : LayoutPoint();
+            if (renderer()->previousPositionFromPaintInvalidationContainer() != geometryMap->mapToContainer(offset, newPaintInvalidationContainer))
+                renderer()->setMayNeedPaintInvalidation(true);

[leviw_travelin_and_unemployed, 2014/06/02 20:47:21]

I still don't love this We're only okay because we're guaranteed to do a full
walk with a RenderGeometryMap, right? We don't really need to update the
repaintContainer in the other cases, I just wish we had a way to enforce that we
get into this code in the full-walk case we need it in.

I'd recommend assigning paintInvalidationContainer to null when we don't have a
geometry map to document where/how this is used and to avoid the unnecessary
work in other cases, and maybe add a comment about the reason we can gate the
code on having a geometryMap.

[dsinclair, 2014/06/02 20:58:07]

Done. Is this better?

+        }
+    }
+
     repainter().repaintAfterLayout(flags & CheckForRepaint);
 
     // Go ahead and update the reflection's position and size.
@@ -313,7 +325,7 @@ void RenderLayer::updateLayerPositions(RenderGeometryMap* geometryMap, UpdateLay
         flags |= UpdatePagination;
 
     for (RenderLayer* child = firstChild(); child; child = child->nextSibling())
-        child->updateLayerPositions(geometryMap, flags);
+        child->updateLayerPositions(geometryMap, newPaintInvalidationContainer, flags);
 
     if ((flags & NeedsFullRepaintInBacking) && hasCompositedLayerMapping() && !compositedLayerMapping()->paintsIntoCompositedAncestor())
         compositedLayerMapping()->setContentsNeedDisplay();
@@ -1483,7 +1495,7 @@ void RenderLayer::removeOnlyThisLayer()
         // Hits in compositing/overflow/automatically-opt-into-composited-scrolling-part-1.html
         DisableCompositingQueryAsserts disabler;
 
-        current->updateLayerPositions(0); // FIXME: use geometry map.
+        current->updateLayerPositions(0, 0); // FIXME: use geometry map.
         current = next;
     }