Remove deprecated methods from Pickle.

net/http/http_response_headers.cc

Index: net/http/http_response_headers.cc
diff --git a/net/http/http_response_headers.cc b/net/http/http_response_headers.cc
index 91673f48fecf852f5743de17d681a136cc0e65de..c3fd9581b7ce886c7359551fdad46df9bb4a9727 100644
--- a/net/http/http_response_headers.cc
+++ b/net/http/http_response_headers.cc
@@ -156,11 +156,10 @@ HttpResponseHeaders::HttpResponseHeaders(const std::string& raw_input)
                                    HttpUtil::GetStatusCodesForHistogram());
 }
 
-HttpResponseHeaders::HttpResponseHeaders(const Pickle& pickle,
-                                         PickleIterator* iter)
+HttpResponseHeaders::HttpResponseHeaders(PickleIterator* iter)
     : response_code_(-1) {
   std::string raw_input;
-  if (pickle.ReadString(iter, &raw_input))
+  if (iter->ReadString(&raw_input))
     Parse(raw_input);
 }