Mark when we may have been invalidated to early out on repaintTreeAfterLayout.

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 66e6126d4009e68919bbc0b2771651602a68ec54..a7b4d75a80a1e7a4a565eec948246a377757af24 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -362,8 +362,12 @@ void RenderBlock::styleDidChange(StyleDifference diff, const RenderStyle* oldSty
 
 void RenderBlock::repaintTreeAfterLayout()
 {
+    bool maybeInvalidated = mayNeedInvalidation();
     RenderBox::repaintTreeAfterLayout();
 
+    if (!maybeInvalidated)
+        return;
+
     // 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();
@@ -1625,6 +1629,7 @@ void RenderBlock::layoutPositionedObjects(bool relayoutChildren, PositionedLayou
 
         // FIXME: this should only be set from clearNeedsLayout crbug.com/361250
         r->setLayoutDidGetCalled(true);
+        r->setMayNeedInvalidation(true);
 
         SubtreeLayoutScope layoutScope(*r);
         // A fixed position element with an absolute positioned ancestor has no way of knowing if the latter has changed position. So