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

net/http2/hpack/decoder/hpack_entry_type_decoder.h

Index: net/http2/hpack/decoder/hpack_entry_type_decoder.h
diff --git a/net/http2/hpack/decoder/hpack_entry_type_decoder.h b/net/http2/hpack/decoder/hpack_entry_type_decoder.h
new file mode 100644
index 0000000000000000000000000000000000000000..d2c1f54d219f9b059b9584ebf8315d14d59bc8f6
--- /dev/null
+++ b/net/http2/hpack/decoder/hpack_entry_type_decoder.h
@@ -0,0 +1,56 @@
+// 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.
+
+#ifndef NET_HTTP2_HPACK_DECODER_HPACK_ENTRY_TYPE_DECODER_H_
+#define NET_HTTP2_HPACK_DECODER_HPACK_ENTRY_TYPE_DECODER_H_
+
+// Decodes the type of an HPACK entry, and the variable length integer whose
+// prefix is in the low-order bits of the same byte, "below" the type bits.
+// The integer represents an index into static or dynamic table, which may be
+// zero, or is the new size limit of the dynamic table.
+
+#include <string>
+
+#include "base/logging.h"
+#include "net/base/net_export.h"
+#include "net/http2/decoder/decode_buffer.h"
+#include "net/http2/decoder/decode_status.h"
+#include "net/http2/hpack/decoder/hpack_varint_decoder.h"
+#include "net/http2/hpack/http2_hpack_constants.h"
+
+namespace net {
+
+class NET_EXPORT_PRIVATE HpackEntryTypeDecoder {
+ public:
+  // Only call when the decode buffer has data (i.e. HpackEntryDecoder must
+  // not call until there is data).
+  DecodeStatus Start(DecodeBuffer* db);
+
+  // Only call Resume if the previous call (Start or Resume) returned
+  // DecodeStatus::kDecodeInProgress.
+  DecodeStatus Resume(DecodeBuffer* db) { return varint_decoder_.Resume(db); }
+
+  // Returns the decoded entry type. Only call if the preceding call to Start
+  // or Resume returned kDecodeDone.
+  HpackEntryType entry_type() const { return entry_type_; }
+
+  // Returns the decoded variable length integer. Only call if the
+  // preceding call to Start or Resume returned kDecodeDone.
+  uint32_t varint() const { return varint_decoder_.value(); }
+
+  std::string DebugString() const;
+
+ private:
+  HpackVarintDecoder varint_decoder_;
+
+  // This field is initialized just to keep ASAN happy about reading it
+  // from DebugString().
+  HpackEntryType entry_type_ = HpackEntryType::kIndexedHeader;
+};
+
+NET_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& out,
+                                            const HpackEntryTypeDecoder& v);
+
+}  // namespace net
+#endif  // NET_HTTP2_HPACK_DECODER_HPACK_ENTRY_TYPE_DECODER_H_