Revert of Add new HTTP/2 and HPACK decoder in net/http2/.

net/http2/hpack/http2_hpack_constants.cc

-// Copyright 2016 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/http2/hpack/http2_hpack_constants.h"
-
-#include <sstream>
-
-namespace net {
-
-std::string HpackEntryTypeToString(HpackEntryType v) {
-  switch (v) {
-    case HpackEntryType::kIndexedHeader:
-      return "kIndexedHeader";
-    case HpackEntryType::kDynamicTableSizeUpdate:
-      return "kDynamicTableSizeUpdate";
-    case HpackEntryType::kIndexedLiteralHeader:
-      return "kIndexedLiteralHeader";
-    case HpackEntryType::kUnindexedLiteralHeader:
-      return "kUnindexedLiteralHeader";
-    case HpackEntryType::kNeverIndexedLiteralHeader:
-      return "kNeverIndexedLiteralHeader";
-  }
-  std::stringstream ss;
-  ss << "UnknownHpackEntryType(" << static_cast<int>(v) << ")";
-  return ss.str();
-}
-
-std::ostream& operator<<(std::ostream& out, HpackEntryType v) {
-  return out << HpackEntryTypeToString(v);
-}
-
-}  // namespace net