Introduce AncestorThrottle, which will process 'X-Frame-Options' headers.

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

Index: third_party/WebKit/Source/platform/network/HTTPParsers.h
diff --git a/third_party/WebKit/Source/platform/network/HTTPParsers.h b/third_party/WebKit/Source/platform/network/HTTPParsers.h
index 8fe5d2e95d6e571115490d6870eab92866eb1c88..f7453cd1a75b32cc162ed9634fa22bcda9d40915 100644
--- a/third_party/WebKit/Source/platform/network/HTTPParsers.h
+++ b/third_party/WebKit/Source/platform/network/HTTPParsers.h
@@ -54,14 +54,6 @@ enum ContentTypeOptionsDisposition {
     ContentTypeOptionsNosniff
 };
 
-enum XFrameOptionsDisposition {
-    XFrameOptionsInvalid,
-    XFrameOptionsDeny,
-    XFrameOptionsSameOrigin,
-    XFrameOptionsAllowAll,
-    XFrameOptionsConflict
-};
-
 // Be sure to update the behavior of XSSAuditor::combineXSSProtectionHeaderAndCSP whenever you change this enum's content or ordering.
 enum ReflectedXSSDisposition {
     ReflectedXSSUnset = 0,
@@ -109,7 +101,6 @@ PLATFORM_EXPORT AtomicString extractMIMETypeFromMediaType(const AtomicString&);
 PLATFORM_EXPORT String extractCharsetFromMediaType(const String&);
 PLATFORM_EXPORT void findCharsetInMediaType(const String& mediaType, unsigned& charsetPos, unsigned& charsetLen, unsigned start = 0);
 PLATFORM_EXPORT ReflectedXSSDisposition parseXSSProtectionHeader(const String& header, String& failureReason, unsigned& failurePosition, String& reportURL);
-PLATFORM_EXPORT XFrameOptionsDisposition parseXFrameOptionsHeader(const String&);
 PLATFORM_EXPORT CacheControlHeader parseCacheControlDirectives(const AtomicString& cacheControlHeader, const AtomicString& pragmaHeader);
 PLATFORM_EXPORT void parseCommaDelimitedHeader(const String& headerValue, CommaDelimitedHeaderSet&);
 // Returns true on success, otherwise false. The Suborigin argument must be a