Remove hidden elements from MHTML

third_party/WebKit/Source/web/WebFrameSerializer.cpp

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 63 matching lines @@
 namespace blink {
 
 namespace {
 
 class MHTMLFrameSerializerDelegate final : public FrameSerializer::Delegate {
   WTF_MAKE_NONCOPYABLE(MHTMLFrameSerializerDelegate);
 
  public:
   explicit MHTMLFrameSerializerDelegate(
       WebFrameSerializer::MHTMLPartsGenerationDelegate&);
+  bool shouldIgnoreElement(const Element&) override;
   bool shouldIgnoreAttribute(const Element&, const Attribute&) override;
   bool rewriteLink(const Element&, String& rewrittenLink) override;
   bool shouldSkipResourceWithURL(const KURL&) override;
   bool shouldSkipResource(
       FrameSerializer::ResourceHasCacheControlNoStoreHeader) override;
   Vector<Attribute> getCustomAttributes(const Element&) override;
 
  private:
   WebFrameSerializer::MHTMLPartsGenerationDelegate& m_webDelegate;
 };
 
 MHTMLFrameSerializerDelegate::MHTMLFrameSerializerDelegate(
     WebFrameSerializer::MHTMLPartsGenerationDelegate& webDelegate)
     : m_webDelegate(webDelegate) {}
 
+bool MHTMLFrameSerializerDelegate::shouldIgnoreElement(const Element& element) {
+  // Do not include elements that are are set to hidden without affecting layout
+  // by the page. For those elements that are hidden by default, they will not
+  // be excluded:
+  // 1) All elements that are head or part of head, including head, meta, style,
+  //    link and etc.
+  // 2) Some specific elements in body: meta, datalist, option and etc.
+  if (element.layoutObject())
+    return false;
+  if (isHTMLHeadElement(element) || isHTMLMetaElement(element) ||
+      isHTMLDataListElement(element) || isHTMLOptionElement(element)) {
+    return false;
+  }
+  Element* parent = element.parentElement();
+  return parent && !isHTMLHeadElement(parent);
+}
+
 bool MHTMLFrameSerializerDelegate::shouldIgnoreAttribute(
     const Element& element,
     const Attribute& attribute) {
   // TODO(fgorski): Presence of srcset attribute causes MHTML to not display
   // images, as only the value of src is pulled into the archive. Discarding
   // srcset prevents the problem. Long term we should make sure to MHTML plays
   // nicely with srcset.
   if (attribute.localName() == HTMLNames::srcsetAttr)
     return true;
 
@@ skipping 234 matching lines @@
     const WebString& baseTarget) {
   // TODO(yosin) We should call |FrameSerializer::baseTagDeclarationOf()|.
   if (baseTarget.isEmpty())
     return String("<base href=\".\">");
   String baseString = "<base href=\".\" target=\"" +
                       static_cast<const String&>(baseTarget) + "\">";
   return baseString;
 }
 
 }  // namespace blink