Merge 124888

Source/WebCore/rendering/RenderFullScreen.cpp

Index: Source/WebCore/rendering/RenderFullScreen.cpp
===================================================================
--- Source/WebCore/rendering/RenderFullScreen.cpp	(revision 126658)
+++ Source/WebCore/rendering/RenderFullScreen.cpp	(working copy)
@@ -117,9 +117,20 @@
         // |object->parent()| can be null if the object is not yet attached
         // to |parent|.
         if (RenderObject* parent = object->parent()) {
+            RenderBlock* containingBlock = object->containingBlock();
+            ASSERT(containingBlock);
+            // Since we are moving the |object| to a new parent |fullscreenRenderer|,
+            // the line box tree underneath our |containingBlock| is not longer valid.
+            containingBlock->deleteLineBoxTree();
+
             parent->addChild(fullscreenRenderer, object);
             object->remove();
+            
+            // Always just do a full layout to ensure that line boxes get deleted properly.
+            // Because objects moved from |parent| to |fullscreenRenderer|, we want to
+            // make new line boxes instead of leaving the old ones around.
             parent->setNeedsLayoutAndPrefWidthsRecalc();
+            containingBlock->setNeedsLayoutAndPrefWidthsRecalc();
         }
         fullscreenRenderer->addChild(object);
         fullscreenRenderer->setNeedsLayoutAndPrefWidthsRecalc();