diff --git a/xz_extent_writer.h b/xz_extent_writer.h
new file mode 100644
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--- /dev/null
+++ b/xz_extent_writer.h
@@ -0,0 +1,60 @@
+//
+// Copyright (C) 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef UPDATE_ENGINE_XZ_EXTENT_WRITER_H_
+#define UPDATE_ENGINE_XZ_EXTENT_WRITER_H_
+
+#include <xz.h>
+
+#include <memory>
+#include <vector>
+
+#include <chromeos/secure_blob.h>
+
+#include "update_engine/extent_writer.h"
+
+// XzExtentWriter is a concrete ExtentWriter subclass that xz-decompresses
+// what it's given in Write using xz-embedded. Note that xz-embedded only
+// supports files with either no CRC or CRC-32. It passes the decompressed data
+// to an underlying ExtentWriter.
+
+namespace chromeos_update_engine {
+
+class XzExtentWriter : public ExtentWriter {
+ public:
+  explicit XzExtentWriter(std::unique_ptr<ExtentWriter> underlying_writer)
+      : underlying_writer_(std::move(underlying_writer)) {}
+  ~XzExtentWriter() override;
+
+  bool Init(FileDescriptorPtr fd,
+            const std::vector<Extent>& extents,
+            uint32_t block_size) override;
+  bool Write(const void* bytes, size_t count) override;
+  bool EndImpl() override;
+
+ private:
+  // The underlying ExtentWriter.
+  std::unique_ptr<ExtentWriter> underlying_writer_;
+  // The opaque xz decompressor struct.
+  xz_dec* stream_{nullptr};
+  chromeos::Blob input_buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(XzExtentWriter);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_XZ_EXTENT_WRITER_H_