[RAL] Make sure RenderLayers are invalidated when moved.

Source/core/rendering/RenderBlock.cpp

Index: Source/core/rendering/RenderBlock.cpp
diff --git a/Source/core/rendering/RenderBlock.cpp b/Source/core/rendering/RenderBlock.cpp
index a95ad9ee2a5fb8d4cc81f71a43687feab0881aa4..e48a7499329b4c2b5ce32019b6d7d2ba30194663 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -365,8 +365,9 @@ void RenderBlock::styleDidChange(StyleDifference diff, const RenderStyle* oldSty
 
 void RenderBlock::repaintTreeAfterLayout(const RenderLayerModelObject& repaintContainer)
 {
-    if (!shouldCheckForInvalidationAfterLayout())
-        return;
+    // Note, we don't want to early out here using shouldCheckForInvalidationAfterLayout as
+    // we have to make sure we go through any positioned objects as they won't be seen in
+    // the normal tree walk.
 
     RenderBox::repaintTreeAfterLayout(repaintContainer);

[ojan, 2014/05/24 05:14:29]

Can this be: 
if (shouldCheckForInvalidationAfterLayout())
    RenderBox::repaintTreeAfterLayout(repaintContainer);

If it can't, then the comment is not quite sufficient as it only talks about
positioned objects.

[dsinclair, 2014/05/26 14:57:25]

Done. I didn't bother before since the RenderBox version has the same check but
this saves us calling the repaintTreeAfterLayout method at all.

 
@@ -381,6 +382,17 @@ void RenderBlock::repaintTreeAfterLayout(const RenderLayerModelObject& repaintCo
             // so we can't pass our own repaint container along.
             const RenderLayerModelObject& repaintContainerForChild = *box->containerForRepaint();
 
+            // When a floating object is moved the children do not get layout but they get a new position.
+            // We have to make sure we invalidate the children if a floating parent container moves.
+            if (isFloating() || isRelPositioned()) {
+                if (box->previousPositionFromRepaintContainer() != box->positionFromRepaintContainer(&repaintContainerForChild)) {
+                    // Note, this has to be non-recursive. If we walk up the tree we'll end up setting
+                    // the flag on our parent who has already cleared their flags for this invalidation
+                    // walk. We also don't have to force them to walk as we're all ready there.
+                    box->setMayNeedInvalidationNonRecursive(true);
+                }
+            }
+
             // If the positioned renderer is absolutely positioned and it is inside
             // a relatively positioend inline element, we need to account for
             // the inline elements position in LayoutState.