A frameset tag inside template should be simply ignored.

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

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  * Copyright (C) 2011, 2014 Apple 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
@@ skipping 912 matching lines @@
         return;
     }
     m_tree.reconstructTheActiveFormattingElements();
     m_tree.insertHTMLElement(token);
 }
 
 void HTMLTreeBuilder::processTemplateStartTag(AtomicHTMLToken* token)
 {
     m_tree.activeFormattingElements()->appendMarker();
     m_tree.insertHTMLElement(token);
+    m_framesetOk = false;
     m_templateInsertionModes.append(TemplateContentsMode);
     setInsertionMode(TemplateContentsMode);
 }
 
 bool HTMLTreeBuilder::processTemplateEndTag(AtomicHTMLToken* token)
 {
     ASSERT(token->name() == templateTag.localName());
     if (!m_tree.openElements()->hasTemplateInHTMLScope()) {
         ASSERT(m_templateInsertionModes.isEmpty() || (m_templateInsertionModes.size() == 1 && isHTMLTemplateElement(m_fragmentContext.contextElement())));
         parseError(token);
@@ skipping 1877 matching lines @@
     ASSERT(m_isAttached);
     // Warning, this may detach the parser. Do not do anything else after this.
     m_tree.finishedParsing();
 }
 
 void HTMLTreeBuilder::parseError(AtomicHTMLToken*)
 {
 }
 
 } // namespace blink