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

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

Index: third_party/WebKit/Source/platform/network/ResourceError.h
diff --git a/third_party/WebKit/Source/platform/network/ResourceError.h b/third_party/WebKit/Source/platform/network/ResourceError.h
index 6dea74de1212aa1de51655ef98a423ebf63d6882..e35325db039397dfa87277d3429f4f4c32e0ff60 100644
--- a/third_party/WebKit/Source/platform/network/ResourceError.h
+++ b/third_party/WebKit/Source/platform/network/ResourceError.h
@@ -27,6 +27,7 @@
 #ifndef ResourceError_h
 #define ResourceError_h
 
+#include "net/base/net_errors.h"
 #include "platform/PlatformExport.h"
 #include "wtf/Allocator.h"
 #include "wtf/text/WTFString.h"
@@ -91,6 +92,8 @@ public:
     void setWasIgnoredByHandler(bool ignoredByHandler) { m_wasIgnoredByHandler = ignoredByHandler; }
     bool wasIgnoredByHandler() const { return m_wasIgnoredByHandler; }
 
+    bool wasBlockedByResponse() const { return m_errorCode == net::ERR_BLOCKED_BY_RESPONSE; }
+
     static bool compare(const ResourceError&, const ResourceError&);
 
 private: