Revert of Avoids the "re-encode HPACK as SPDY3" step.

net/quic/spdy_utils.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/spdy_utils.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/stl_util.h"
@@ skipping 102 matching lines @@
 bool SpdyUtils::CopyAndValidateHeaders(const QuicHeaderList& header_list,
                                        int64_t* content_length,
                                        SpdyHeaderBlock* headers) {
   for (const auto& p : header_list) {
     const string& name = p.first;
     if (name.empty()) {
       DVLOG(1) << "Header name must not be empty.";
       return false;
     }
 
+    if (std::any_of(name.begin(), name.end(), base::IsAsciiUpper<char>)) {
+      DLOG(ERROR) << "Malformed header: Header name " << name
+                  << " contains upper-case characters.";
+      return false;
+    }
+
     auto iter = headers->find(name);
     if (iter == headers->end()) {
       (*headers)[name] = p.second;
     } else if (name == "cookie") {
       // Obeys section 8.1.2.5 in RFC 7540 for cookie reconstruction.
       headers->ReplaceOrAppendHeader(
           name, base::StringPrintf("%s; %s", iter->second.as_string().c_str(),
                                    p.second.c_str()));
     } else {
       // This header had multiple values, so it must be reconstructed.
@@ skipping 109 matching lines @@
   return GURL(GetUrlFromHeaderBlock(headers)).host();
 }
 
 // static
 bool SpdyUtils::UrlIsValid(const SpdyHeaderBlock& headers) {
   string url(GetUrlFromHeaderBlock(headers));
   return url != "" && GURL(url).is_valid();
 }
 
 }  // namespace net