diff --git a/http2/decoder/payload_decoders/window_update_payload_decoder.h b/http2/decoder/payload_decoders/window_update_payload_decoder.h
new file mode 100644
index 0000000..158c165
--- /dev/null
+++ b/http2/decoder/payload_decoders/window_update_payload_decoder.h
@@ -0,0 +1,42 @@
+// 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 QUICHE_HTTP2_DECODER_PAYLOAD_DECODERS_WINDOW_UPDATE_PAYLOAD_DECODER_H_
+#define QUICHE_HTTP2_DECODER_PAYLOAD_DECODERS_WINDOW_UPDATE_PAYLOAD_DECODER_H_
+
+// Decodes the payload of a WINDOW_UPDATE frame.
+
+#include "net/third_party/quiche/src/http2/decoder/decode_buffer.h"
+#include "net/third_party/quiche/src/http2/decoder/decode_status.h"
+#include "net/third_party/quiche/src/http2/decoder/frame_decoder_state.h"
+#include "net/third_party/quiche/src/http2/http2_structures.h"
+#include "net/third_party/quiche/src/http2/platform/api/http2_export.h"
+
+namespace http2 {
+namespace test {
+class WindowUpdatePayloadDecoderPeer;
+}  // namespace test
+
+class HTTP2_EXPORT_PRIVATE WindowUpdatePayloadDecoder {
+ public:
+  // Starts decoding a WINDOW_UPDATE frame's payload, and completes it if
+  // the entire payload is in the provided decode buffer.
+  DecodeStatus StartDecodingPayload(FrameDecoderState* state, DecodeBuffer* db);
+
+  // Resumes decoding a WINDOW_UPDATE frame's payload that has been split across
+  // decode buffers.
+  DecodeStatus ResumeDecodingPayload(FrameDecoderState* state,
+                                     DecodeBuffer* db);
+
+ private:
+  friend class test::WindowUpdatePayloadDecoderPeer;
+
+  DecodeStatus HandleStatus(FrameDecoderState* state, DecodeStatus status);
+
+  Http2WindowUpdateFields window_update_fields_;
+};
+
+}  // namespace http2
+
+#endif  // QUICHE_HTTP2_DECODER_PAYLOAD_DECODERS_WINDOW_UPDATE_PAYLOAD_DECODER_H_