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

net/http2/hpack/decoder/hpack_string_decoder.cc

Index: net/http2/hpack/decoder/hpack_string_decoder.cc
diff --git a/net/http2/hpack/decoder/hpack_string_decoder.cc b/net/http2/hpack/decoder/hpack_string_decoder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4131e01b5ce1dd85a8e55e8cdb67df490315d2ae
--- /dev/null
+++ b/net/http2/hpack/decoder/hpack_string_decoder.cc
@@ -0,0 +1,39 @@
+// 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/decoder/hpack_string_decoder.h"
+
+#include <sstream>
+
+namespace net {
+
+std::string HpackStringDecoder::DebugString() const {
+  std::stringstream ss;
+  ss << "HpackStringDecoder(state=" << StateToString(state_)
+     << ", length=" << length_decoder_.DebugString()
+     << ", remaining=" << remaining_
+     << ", huffman=" << (huffman_encoded_ ? "true)" : "false)");
+  return ss.str();
+}
+
+// static
+std::string HpackStringDecoder::StateToString(StringDecoderState v) {
+  switch (v) {
+    case kStartDecodingLength:
+      return "kStartDecodingLength";
+    case kDecodingString:
+      return "kDecodingString";
+    case kResumeDecodingLength:
+      return "kResumeDecodingLength";
+  }
+  std::stringstream ss;
+  ss << "UNKNOWN_STATE(" << static_cast<uint32_t>(v) << ")";
+  return ss.str();
+}
+
+std::ostream& operator<<(std::ostream& out, const HpackStringDecoder& v) {
+  return out << v.DebugString();
+}
+
+}  // namespace net