Disable form elements in MHTML

third_party/WebKit/Source/core/frame/FrameSerializer.cpp

Index: third_party/WebKit/Source/core/frame/FrameSerializer.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameSerializer.cpp b/third_party/WebKit/Source/core/frame/FrameSerializer.cpp
index 382e411bdae9c375b44ffd8ad7e21c86fd389f03..d1d4ed2a3f59a2f904531380d21eb45baa4f04af 100644
--- a/third_party/WebKit/Source/core/frame/FrameSerializer.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameSerializer.cpp
@@ -98,6 +98,9 @@ class SerializerMarkupAccumulator : public MarkupAccumulator {
   ~SerializerMarkupAccumulator() override;
 
  protected:
+  void appendCustomAttributes(StringBuilder&,
+                              const Element&,
+                              Namespaces*) override;
   void appendText(StringBuilder& out, Text&) override;
   bool shouldIgnoreAttribute(const Element&, const Attribute&) override;
   void appendElement(StringBuilder& out, Element&, Namespaces*) override;
@@ -139,6 +142,15 @@ SerializerMarkupAccumulator::SerializerMarkupAccumulator(
 
 SerializerMarkupAccumulator::~SerializerMarkupAccumulator() {}
 
+void SerializerMarkupAccumulator::appendCustomAttributes(
+    StringBuilder& result,
+    const Element& element,
+    Namespaces* namespaces) {
+  Vector<Attribute> attributes = m_delegate.getCustomAttributes(element);
+  for (const auto& attribute : attributes)
+    appendAttribute(result, element, attribute, namespaces);
+}
+
 void SerializerMarkupAccumulator::appendText(StringBuilder& result,
                                              Text& text) {
   Element* parent = text.parentElement();