Handle some failing DocumentOrderedMap ID lookups across tree removals.

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

Index: third_party/WebKit/Source/core/dom/ContainerNode.cpp
diff --git a/third_party/WebKit/Source/core/dom/ContainerNode.cpp b/third_party/WebKit/Source/core/dom/ContainerNode.cpp
index 1e2fe05deb8fd395510513ca71914d9918336852..13c682ff9ff5507d0b4d3c182d5ef9c0b495334f 100644
--- a/third_party/WebKit/Source/core/dom/ContainerNode.cpp
+++ b/third_party/WebKit/Source/core/dom/ContainerNode.cpp
@@ -586,7 +586,9 @@ PassRefPtrWillBeRawPtr<Node> ContainerNode::removeChild(PassRefPtrWillBeRawPtr<N
 
     {
         HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
-
+#if ENABLE(ASSERT)
+        TreeScope::RemoveScope treeRemoveScope(this);

[esprehn, 2016/01/05 07:48:33]

DocumentOrderedMap::RemoveScope

+#endif
         Node* prev = child->previousSibling();
         Node* next = child->nextSibling();
         removeBetween(prev, next, *child);
@@ -638,6 +640,9 @@ void ContainerNode::parserRemoveChild(Node& oldChild)
     oldChild.notifyMutationObserversNodeWillDetach();
 
     HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
+#if ENABLE(ASSERT)
+    TreeScope::RemoveScope treeRemoveScope(this);

[esprehn, 2016/01/05 07:48:33]

no need to pass anything if you just increment the static, this can just be

DocumentOrderedMap::RemoveScope removeScope;

which compiles into a no-op without ASSERTs.

+#endif
     Node* prev = oldChild.previousSibling();
     Node* next = oldChild.nextSibling();
     removeBetween(prev, next, oldChild);
@@ -685,7 +690,9 @@ void ContainerNode::removeChildren(SubtreeModificationAction action)
 #endif
     {
         HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
-
+#if ENABLE(ASSERT)
+        TreeScope::RemoveScope treeRemoveScope(this);
+#endif
         {
             EventDispatchForbiddenScope assertNoEventDispatch;
             ScriptForbiddenScope forbidScript;