diff --git a/http2/decoder/payload_decoders/altsvc_payload_decoder.cc b/http2/decoder/payload_decoders/altsvc_payload_decoder.cc
new file mode 100644
index 0000000..4e4d860
--- /dev/null
+++ b/http2/decoder/payload_decoders/altsvc_payload_decoder.cc
@@ -0,0 +1,148 @@
+// 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/third_party/quiche/src/http2/decoder/payload_decoders/altsvc_payload_decoder.h"
+
+#include <stddef.h>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "net/third_party/quiche/src/http2/decoder/decode_buffer.h"
+#include "net/third_party/quiche/src/http2/decoder/http2_frame_decoder_listener.h"
+#include "net/third_party/quiche/src/http2/http2_constants.h"
+#include "net/third_party/quiche/src/http2/http2_structures.h"
+#include "net/third_party/quiche/src/http2/platform/api/http2_bug_tracker.h"
+#include "net/third_party/quiche/src/http2/platform/api/http2_macros.h"
+
+namespace http2 {
+
+std::ostream& operator<<(std::ostream& out,
+                         AltSvcPayloadDecoder::PayloadState v) {
+  switch (v) {
+    case AltSvcPayloadDecoder::PayloadState::kStartDecodingStruct:
+      return out << "kStartDecodingStruct";
+    case AltSvcPayloadDecoder::PayloadState::kMaybeDecodedStruct:
+      return out << "kMaybeDecodedStruct";
+    case AltSvcPayloadDecoder::PayloadState::kDecodingStrings:
+      return out << "kDecodingStrings";
+    case AltSvcPayloadDecoder::PayloadState::kResumeDecodingStruct:
+      return out << "kResumeDecodingStruct";
+  }
+  // Since the value doesn't come over the wire, only a programming bug should
+  // result in reaching this point.
+  int unknown = static_cast<int>(v);
+  HTTP2_BUG << "Invalid AltSvcPayloadDecoder::PayloadState: " << unknown;
+  return out << "AltSvcPayloadDecoder::PayloadState(" << unknown << ")";
+}
+
+DecodeStatus AltSvcPayloadDecoder::StartDecodingPayload(
+    FrameDecoderState* state,
+    DecodeBuffer* db) {
+  DVLOG(2) << "AltSvcPayloadDecoder::StartDecodingPayload: "
+           << state->frame_header();
+  DCHECK_EQ(Http2FrameType::ALTSVC, state->frame_header().type);
+  DCHECK_LE(db->Remaining(), state->frame_header().payload_length);
+  DCHECK_EQ(0, state->frame_header().flags);
+
+  state->InitializeRemainders();
+  payload_state_ = PayloadState::kStartDecodingStruct;
+
+  return ResumeDecodingPayload(state, db);
+}
+
+DecodeStatus AltSvcPayloadDecoder::ResumeDecodingPayload(
+    FrameDecoderState* state,
+    DecodeBuffer* db) {
+  const Http2FrameHeader& frame_header = state->frame_header();
+  DVLOG(2) << "AltSvcPayloadDecoder::ResumeDecodingPayload: " << frame_header;
+  DCHECK_EQ(Http2FrameType::ALTSVC, frame_header.type);
+  DCHECK_LE(state->remaining_payload(), frame_header.payload_length);
+  DCHECK_LE(db->Remaining(), state->remaining_payload());
+  DCHECK_NE(PayloadState::kMaybeDecodedStruct, payload_state_);
+  // |status| has to be initialized to some value to avoid compiler error in
+  // case PayloadState::kMaybeDecodedStruct below, but value does not matter,
+  // see DCHECK_NE above.
+  DecodeStatus status = DecodeStatus::kDecodeError;
+  while (true) {
+    DVLOG(2) << "AltSvcPayloadDecoder::ResumeDecodingPayload payload_state_="
+             << payload_state_;
+    switch (payload_state_) {
+      case PayloadState::kStartDecodingStruct:
+        status = state->StartDecodingStructureInPayload(&altsvc_fields_, db);
+        HTTP2_FALLTHROUGH;
+
+      case PayloadState::kMaybeDecodedStruct:
+        if (status == DecodeStatus::kDecodeDone &&
+            altsvc_fields_.origin_length <= state->remaining_payload()) {
+          size_t origin_length = altsvc_fields_.origin_length;
+          size_t value_length = state->remaining_payload() - origin_length;
+          state->listener()->OnAltSvcStart(frame_header, origin_length,
+                                           value_length);
+        } else if (status != DecodeStatus::kDecodeDone) {
+          DCHECK(state->remaining_payload() > 0 ||
+                 status == DecodeStatus::kDecodeError)
+              << "\nremaining_payload: " << state->remaining_payload()
+              << "\nstatus: " << status << "\nheader: " << frame_header;
+          // Assume in progress.
+          payload_state_ = PayloadState::kResumeDecodingStruct;
+          return status;
+        } else {
+          // The origin's length is longer than the remaining payload.
+          DCHECK_GT(altsvc_fields_.origin_length, state->remaining_payload());
+          return state->ReportFrameSizeError();
+        }
+        HTTP2_FALLTHROUGH;
+
+      case PayloadState::kDecodingStrings:
+        return DecodeStrings(state, db);
+
+      case PayloadState::kResumeDecodingStruct:
+        status = state->ResumeDecodingStructureInPayload(&altsvc_fields_, db);
+        payload_state_ = PayloadState::kMaybeDecodedStruct;
+        continue;
+    }
+    HTTP2_BUG << "PayloadState: " << payload_state_;
+  }
+}
+
+DecodeStatus AltSvcPayloadDecoder::DecodeStrings(FrameDecoderState* state,
+                                                 DecodeBuffer* db) {
+  DVLOG(2) << "AltSvcPayloadDecoder::DecodeStrings remaining_payload="
+           << state->remaining_payload()
+           << ", db->Remaining=" << db->Remaining();
+  // Note that we don't explicitly keep track of exactly how far through the
+  // origin; instead we compute it from how much is left of the original
+  // payload length and the decoded total length of the origin.
+  size_t origin_length = altsvc_fields_.origin_length;
+  size_t value_length = state->frame_header().payload_length - origin_length -
+                        Http2AltSvcFields::EncodedSize();
+  if (state->remaining_payload() > value_length) {
+    size_t remaining_origin_length = state->remaining_payload() - value_length;
+    size_t avail = db->MinLengthRemaining(remaining_origin_length);
+    state->listener()->OnAltSvcOriginData(db->cursor(), avail);
+    db->AdvanceCursor(avail);
+    state->ConsumePayload(avail);
+    if (remaining_origin_length > avail) {
+      payload_state_ = PayloadState::kDecodingStrings;
+      return DecodeStatus::kDecodeInProgress;
+    }
+  }
+  // All that is left is the value string.
+  DCHECK_LE(state->remaining_payload(), value_length);
+  DCHECK_LE(db->Remaining(), state->remaining_payload());
+  if (db->HasData()) {
+    size_t avail = db->Remaining();
+    state->listener()->OnAltSvcValueData(db->cursor(), avail);
+    db->AdvanceCursor(avail);
+    state->ConsumePayload(avail);
+  }
+  if (state->remaining_payload() == 0) {
+    state->listener()->OnAltSvcEnd();
+    return DecodeStatus::kDecodeDone;
+  }
+  payload_state_ = PayloadState::kDecodingStrings;
+  return DecodeStatus::kDecodeInProgress;
+}
+
+}  // namespace http2