Replace ASSERT by null-check in InsertedNodes::lastLeafInserted()

Source/core/editing/ReplaceSelectionCommand.cpp

Index: Source/core/editing/ReplaceSelectionCommand.cpp
diff --git a/Source/core/editing/ReplaceSelectionCommand.cpp b/Source/core/editing/ReplaceSelectionCommand.cpp
index 90ce127d8175518ea113edf0d4ef5e271a199cf5..984c9e076fe29414f4fb19e8cf5871a0575167d2 100644
--- a/Source/core/editing/ReplaceSelectionCommand.cpp
+++ b/Source/core/editing/ReplaceSelectionCommand.cpp
@@ -665,12 +665,12 @@ void ReplaceSelectionCommand::removeUnrenderedTextNodesAtEnds(InsertedNodes& ins
 {
     document().updateLayoutIgnorePendingStylesheets();
 
-    Node& lastLeafInserted = insertedNodes.lastLeafInserted();
-    if (lastLeafInserted.isTextNode() && !nodeHasVisibleRenderText(toText(lastLeafInserted))
-        && !enclosingNodeWithTag(firstPositionInOrBeforeNode(&lastLeafInserted), selectTag)
-        && !enclosingNodeWithTag(firstPositionInOrBeforeNode(&lastLeafInserted), scriptTag)) {
-        insertedNodes.willRemoveNode(lastLeafInserted);
-        removeNode(&lastLeafInserted);
+    Node* lastLeafInserted = insertedNodes.lastLeafInserted();
+    if (lastLeafInserted && lastLeafInserted->isTextNode() && !nodeHasVisibleRenderText(toText(*lastLeafInserted))
+        && !enclosingNodeWithTag(firstPositionInOrBeforeNode(lastLeafInserted), selectTag)
+        && !enclosingNodeWithTag(firstPositionInOrBeforeNode(lastLeafInserted), scriptTag)) {
+        insertedNodes.willRemoveNode(*lastLeafInserted);
+        removeNode(lastLeafInserted);
     }
 
     // We don't have to make sure that firstNodeInserted isn't inside a select or script element, because
@@ -1143,7 +1143,7 @@ void ReplaceSelectionCommand::doApply()
 
     // Setup m_startOfInsertedContent and m_endOfInsertedContent. This should be the last two lines of code that access insertedNodes.
     m_startOfInsertedContent = firstPositionInOrBeforeNode(insertedNodes.firstNodeInserted());
-    m_endOfInsertedContent = lastPositionInOrAfterNode(&insertedNodes.lastLeafInserted());
+    m_endOfInsertedContent = lastPositionInOrAfterNode(insertedNodes.lastLeafInserted());
 
     // Determine whether or not we should merge the end of inserted content with what's after it before we do
     // the start merge so that the start merge doesn't effect our decision.