[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..5996b7b4811bb89f3ac5c95eaed51e1fbe3078fc 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -365,15 +365,19 @@ 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()) {
         TrackedRendererListHashSet::iterator end = positionedObjects->end();
         LayoutStateMaintainer statePusher(*this, isTableRow() ? LayoutSize() : locationOffset());
+
+        bool isFloatingOrRelPositioned = isFloating() || isRelPositioned();

[leviw_travelin_and_unemployed, 2014/05/27 17:27:57]

Can this not be an issue with absPos as well? Can we get a test? Other than that
question, I think this is fine.

         for (TrackedRendererListHashSet::iterator it = positionedObjects->begin(); it != end; ++it) {
             RenderBox* box = *it;
 
@@ -381,6 +385,17 @@ 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 (isFloatingOrRelPositioned) {
+                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 already there.
+                    box->setSelfMayNeedInvalidation(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.