A frameset tag inside template should be simply ignored.

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

Index: third_party/WebKit/Source/core/html/parser/HTMLTreeBuilder.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLTreeBuilder.cpp b/third_party/WebKit/Source/core/html/parser/HTMLTreeBuilder.cpp
index 8ef2234ecf6d917f8a31b2bed8ecb40f5fdb5aff..1ca04b95ce0da59ffc32ffe08f1c064cb5d87641 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLTreeBuilder.cpp
+++ b/third_party/WebKit/Source/core/html/parser/HTMLTreeBuilder.cpp
@@ -930,6 +930,7 @@ void HTMLTreeBuilder::processTemplateStartTag(AtomicHTMLToken* token)
 {
     m_tree.activeFormattingElements()->appendMarker();
     m_tree.insertHTMLElement(token);
+    m_framesetOk = false;
     m_templateInsertionModes.append(TemplateContentsMode);
     setInsertionMode(TemplateContentsMode);
 }