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

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 3b7cb5b8c869f4957b1b4adde95d595a4c4b2bcf..64cf6fd34458cf0d71e8243bf8822014581c2da5 100644
--- a/third_party/WebKit/Source/platform/network/HTTPParsers.cpp
+++ b/third_party/WebKit/Source/platform/network/HTTPParsers.cpp
@@ -508,6 +508,36 @@ ContentTypeOptionsDisposition parseContentTypeOptionsHeader(const String& header
     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