Implement FullScreen using top layer.

Source/core/layout/LayoutBlock.cpp

Index: Source/core/layout/LayoutBlock.cpp
diff --git a/Source/core/layout/LayoutBlock.cpp b/Source/core/layout/LayoutBlock.cpp
index e4fb73ac0da4b56eaa2d6ecf0b41786cbb36f1a9..cb316aba2ac96f05a881b16ef80e12ed2d571699 100644
--- a/Source/core/layout/LayoutBlock.cpp
+++ b/Source/core/layout/LayoutBlock.cpp
@@ -422,11 +422,7 @@ void LayoutBlock::addChildIgnoringContinuation(LayoutObject* newChild, LayoutObj
             // If the requested beforeChild is not one of our children, then this is because
             // there is an anonymous container within this object that contains the beforeChild.
             LayoutObject* beforeChildAnonymousContainer = beforeChildContainer;
-            if (beforeChildAnonymousContainer->isAnonymousBlock()
-                // Full screen layoutObjects and full screen placeholders act as anonymous blocks, not tables:
-                || beforeChildAnonymousContainer->isLayoutFullScreen()
-                || beforeChildAnonymousContainer->isLayoutFullScreenPlaceholder()
-                ) {
+            if (beforeChildAnonymousContainer->isAnonymousBlock()) {
                 // Insert the child into the anonymous block box instead of here.
                 if (newChild->isInline() || newChild->isFloatingOrOutOfFlowPositioned() || beforeChild->parent()->slowFirstChild() != beforeChild)
                     beforeChild->parent()->addChild(newChild, beforeChild);