(Re-)introduce AncestorThrottle to handle 'X-Frame-Options'.

third_party/WebKit/Source/platform/network/HTTPParsers.cpp

 /*
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2011 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:
@@ skipping 561 matching lines @@
   }
 }
 
 ContentTypeOptionsDisposition parseContentTypeOptionsHeader(
     const String& header) {
   if (header.stripWhiteSpace().lower() == "nosniff")
     return ContentTypeOptionsNosniff;
   return ContentTypeOptionsNone;
 }
 
-XFrameOptionsDisposition parseXFrameOptionsHeader(const String& header) {
-  XFrameOptionsDisposition result = XFrameOptionsInvalid;
-
-  if (header.isEmpty())
-    return result;
-
-  Vector<String> headers;
-  header.split(',', headers);
-
-  bool hasValue = false;
-  for (size_t i = 0; i < headers.size(); i++) {
-    String currentHeader = headers[i].stripWhiteSpace();
-    XFrameOptionsDisposition currentValue = XFrameOptionsInvalid;
-    if (equalIgnoringCase(currentHeader, "deny"))
-      currentValue = XFrameOptionsDeny;
-    else if (equalIgnoringCase(currentHeader, "sameorigin"))
-      currentValue = XFrameOptionsSameOrigin;
-    else if (equalIgnoringCase(currentHeader, "allowall"))
-      currentValue = XFrameOptionsAllowAll;
-
-    if (!hasValue)
-      result = currentValue;
-    else if (result != currentValue)
-      return XFrameOptionsConflict;
-    hasValue = true;
-  }
-  return result;
-}
-
 static bool isCacheHeaderSeparator(UChar c) {
   // See RFC 2616, Section 2.2
   switch (c) {
     case '(':
     case ')':
     case '<':
     case '>':
     case '@':
     case ',':
     case ';':
@@ skipping 280 matching lines @@
   StringBuilder sb;
   sb.append("[");
   sb.append(header);
   sb.append("]");
   std::unique_ptr<JSONValue> headerValue =
       parseJSON(sb.toString(), maxParseDepth);
   return JSONArray::from(std::move(headerValue));
 }
 
 }  // namespace blink