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

net/http2/hpack/http2_hpack_constants.cc

Index: net/http2/hpack/http2_hpack_constants.cc
diff --git a/net/http2/hpack/http2_hpack_constants.cc b/net/http2/hpack/http2_hpack_constants.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bc0ee9e9f7a5395be92005d35beed39fa82ccc71
--- /dev/null
+++ b/net/http2/hpack/http2_hpack_constants.cc
@@ -0,0 +1,33 @@
+// 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