Remove deprecated methods from Pickle.

net/http/http_response_headers.h

Index: net/http/http_response_headers.h
diff --git a/net/http/http_response_headers.h b/net/http/http_response_headers.h
index a093df56a9b20c404995982c9b023263d0104776..5b988950adb24b81a8628df85a7b8acdb0eaa227 100644
--- a/net/http/http_response_headers.h
+++ b/net/http/http_response_headers.h
@@ -72,7 +72,7 @@ class NET_EXPORT HttpResponseHeaders
   // Initializes from the representation stored in the given pickle.  The data
   // for this object is found relative to the given pickle_iter, which should
   // be passed to the pickle's various Read* methods.
-  HttpResponseHeaders(const Pickle& pickle, PickleIterator* pickle_iter);
+  explicit HttpResponseHeaders(PickleIterator* pickle_iter);
 
   // Appends a representation of this object to the given pickle.
   // The options argument can be a combination of PersistOptions.