Handle some failing DocumentOrderedMap ID lookups across tree removals.

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

Index: third_party/WebKit/Source/core/dom/TreeScope.cpp
diff --git a/third_party/WebKit/Source/core/dom/TreeScope.cpp b/third_party/WebKit/Source/core/dom/TreeScope.cpp
index d536fa338bfc7b3b18026ab5bd713a888c7d33e8..59ea10298501e83b20164658595f8ea69838ba58 100644
--- a/third_party/WebKit/Source/core/dom/TreeScope.cpp
+++ b/third_party/WebKit/Source/core/dom/TreeScope.cpp
@@ -186,43 +186,11 @@ void TreeScope::addElementById(const AtomicString& elementId, Element* element)
 }
 
 
-#if ENABLE(ASSERT)
-namespace {
-
-class RemovingElementIdScope {
-    STACK_ALLOCATED();
-public:
-    RemovingElementIdScope(DocumentOrderedMap& elementsById, const AtomicString& id)
-        : m_elementsById(&elementsById)
-    {
-        m_elementsById->willRemoveId(id);
-    }
-    ~RemovingElementIdScope()
-    {
-        m_elementsById->willRemoveId(nullAtom);
-    }
-
-private:
-    RawPtrWillBeMember<DocumentOrderedMap> m_elementsById;
-};
-
-}
-#endif
-
 void TreeScope::removeElementById(const AtomicString& elementId, Element* element)
 {
     if (!m_elementsById)
         return;
     m_elementsById->remove(elementId, element);
-#if ENABLE(ASSERT)
-    // Register 'elementId' as being removed. This is done should observers
-    // attempt to also look it up, something that the underlying DocumentOrderedMap
-    // is incapable of answering precisely while an element (and its
-    // children) are being removed from the tree. This is _only_ done to avoid
-    // an assert in DocumentOrderedMap::get() from falsely triggering for such
-    // unusual and unexpected lookups.
-    RemovingElementIdScope removalScope(*m_elementsById, elementId);
-#endif
     m_idTargetObserverRegistry->notifyObservers(elementId);
 }