NOT FOR REVIEW: Fullscreen WIP

third_party/WebKit/Source/core/dom/PseudoElement.cpp

Index: third_party/WebKit/Source/core/dom/PseudoElement.cpp
diff --git a/third_party/WebKit/Source/core/dom/PseudoElement.cpp b/third_party/WebKit/Source/core/dom/PseudoElement.cpp
index d82156feae41c10d020e28babff95bf24fc0b828..01f30554d007c22e30d1417d75b30a729fd53755 100644
--- a/third_party/WebKit/Source/core/dom/PseudoElement.cpp
+++ b/third_party/WebKit/Source/core/dom/PseudoElement.cpp
@@ -29,6 +29,7 @@
 #include "core/dom/FirstLetterPseudoElement.h"
 #include "core/frame/UseCounter.h"
 #include "core/inspector/InspectorInstrumentation.h"
+#include "core/layout/GeneratedChildren.h"
 #include "core/layout/LayoutObject.h"
 #include "core/layout/LayoutQuote.h"
 #include "core/style/ContentData.h"
@@ -125,6 +126,13 @@ void PseudoElement::attachLayoutTree(const AttachContext& context) {
   if (!layoutObject)
     return;
 
+  // This is to ensure that bypassing the canHaveGeneratedChildren check in
+  // StyleResolver::createPseudoElementIfNeeded does not result in the
+  // backdrop pseudo element's layout object becoming the child of a layout
+  // object that doesn't allow children.
+  DCHECK(layoutObject->parent());
+  DCHECK(canHaveGeneratedChildren(*layoutObject->parent()));
+
   ComputedStyle& style = layoutObject->mutableStyleRef();
   if (style.styleType() != PseudoIdBefore && style.styleType() != PseudoIdAfter)
     return;