Do not dispatch events in Document::nodeChildrenWillBeRemoved().

Source/core/dom/ContainerNode.cpp

Index: Source/core/dom/ContainerNode.cpp
diff --git a/Source/core/dom/ContainerNode.cpp b/Source/core/dom/ContainerNode.cpp
index 45c458946b1d84a9607f130c117afc835f66233e..676aac1242c518514d9857dd75f1267b15c5a118 100644
--- a/Source/core/dom/ContainerNode.cpp
+++ b/Source/core/dom/ContainerNode.cpp
@@ -547,9 +547,11 @@ void ContainerNode::removeChildren()
         // This must be later than willRemoveChildren, which might change focus
         // state of a child.
         document().removeFocusedElementOfSubtree(this, true);
+
+        // Removing a node from a selection can cause widget updates.
+        document().nodeChildrenWillBeRemoved(this);
     }
 
-    document().nodeChildrenWillBeRemoved(this);
 
     NodeVector removedChildren;
     {