[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..0c75e0e706ed8df10ae3394f7594136d0c39f345 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -365,10 +365,12 @@ 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);
+    if (shouldCheckForInvalidationAfterLayout())
+        RenderBox::repaintTreeAfterLayout(repaintContainer);
 
     // Take care of positioned objects. This is required as LayoutState keeps a single clip rect.
     if (TrackedRendererListHashSet* positionedObjects = this->positionedObjects()) {
@@ -381,6 +383,17 @@ 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()) {

[Julien - ping for review, 2014/05/27 12:34:53]

Note that this is independent of the child so we could store the result before
the loop.

[dsinclair, 2014/05/27 15:37:13]

Done.

+                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.

[Julien - ping for review, 2014/05/27 12:34:53]

all ready, not already?

[dsinclair, 2014/05/27 15:37:13]

Done.

+                    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.