Deal with frame removal by content scripts

third_party/WebKit/Source/core/html/parser/TextDocumentParser.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 42 matching lines @@
 {
     // In principle, we should create a specialized tree builder for
     // TextDocuments, but instead we re-use the existing HTMLTreeBuilder.
     // We create a fake token and give it to the tree builder rather than
     // sending fake bytes through the front-end of the parser to avoid
     // distrubing the line/column number calculations.
     Vector<Attribute> attributes;
     attributes.append(Attribute(styleAttr, "word-wrap: break-word; white-space: pre-wrap;"));
     AtomicHTMLToken fakePre(HTMLToken::StartTag, preTag.localName(), attributes);
     treeBuilder()->constructTree(&fakePre);
+    if (isStopped())
+        return; // The document could have been detached by an extension while the tree was being constructed.
 
     // Normally we would skip the first \n after a <pre> element, but we don't
     // want to skip the first \n for text documents!
     treeBuilder()->setShouldSkipLeadingNewline(false);
 
     // Although Text Documents expose a "pre" element in their DOM, they
     // act like a <plaintext> tag, so we have to force plaintext mode.
     forcePlaintextForTextDocument();
 
     m_haveInsertedFakePreElement = true;
 }
 
 } // namespace blink