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

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

Index: third_party/WebKit/Source/platform/network/HTTPParsers.cpp
diff --git a/third_party/WebKit/Source/platform/network/HTTPParsers.cpp b/third_party/WebKit/Source/platform/network/HTTPParsers.cpp
index bd5257dece6b4a7ce03560d17ba556f50cd38c51..153c410cbbf8887f48f7092516d1ad9d3552616b 100644
--- a/third_party/WebKit/Source/platform/network/HTTPParsers.cpp
+++ b/third_party/WebKit/Source/platform/network/HTTPParsers.cpp
@@ -579,35 +579,6 @@ ContentTypeOptionsDisposition parseContentTypeOptionsHeader(
   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) {