Import Cobalt 19.master.0.205881
diff --git a/src/content/browser/speech/audio_buffer.h b/src/content/browser/speech/audio_buffer.h
new file mode 100644
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--- /dev/null
+++ b/src/content/browser/speech/audio_buffer.h
@@ -0,0 +1,84 @@
+// Copyright (c) 2012 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 CONTENT_BROWSER_SPEECH_AUDIO_BUFFER_H_
+#define CONTENT_BROWSER_SPEECH_AUDIO_BUFFER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <string>
+
+#include "base/containers/circular_deque.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Models a chunk derived from an AudioBuffer.
+class CONTENT_EXPORT AudioChunk :
+ public base::RefCountedThreadSafe<AudioChunk> {
+ public:
+ explicit AudioChunk(int bytes_per_sample);
+ // Creates a chunk of |length| bytes, initialized to zeros.
+ AudioChunk(size_t length, int bytes_per_sample);
+ AudioChunk(const uint8_t* data, size_t length, int bytes_per_sample);
+
+ bool IsEmpty() const;
+ int bytes_per_sample() const { return bytes_per_sample_; }
+ size_t NumSamples() const;
+ const std::string& AsString() const;
+ int16_t GetSample16(size_t index) const;
+ const int16_t* SamplesData16() const;
+ uint8_t* writable_data() {
+ return reinterpret_cast<uint8_t*>(&data_string_[0]);
+ }
+
+ private:
+ friend class base::RefCountedThreadSafe<AudioChunk>;
+ ~AudioChunk() {}
+
+ std::string data_string_;
+ const int bytes_per_sample_;
+
+ DISALLOW_COPY_AND_ASSIGN(AudioChunk);
+};
+
+// Models an audio buffer. The current implementation relies on on-demand
+// allocations of AudioChunk(s) (which uses a string as storage).
+class AudioBuffer {
+ public:
+ explicit AudioBuffer(int bytes_per_sample);
+ ~AudioBuffer();
+
+ // Enqueues a copy of |length| bytes of |data| buffer.
+ void Enqueue(const uint8_t* data, size_t length);
+
+ // Dequeues, in FIFO order, a single chunk respecting the length of the
+ // corresponding Enqueue call (in a nutshell: multiple Enqueue calls followed
+ // by DequeueSingleChunk calls will return the individual chunks without
+ // merging them).
+ scoped_refptr<AudioChunk> DequeueSingleChunk();
+
+ // Dequeues all previously enqueued chunks, merging them in a single chunk.
+ scoped_refptr<AudioChunk> DequeueAll();
+
+ // Removes and frees all the enqueued chunks.
+ void Clear();
+
+ // Checks whether the buffer is empty.
+ bool IsEmpty() const;
+
+ private:
+ using ChunksContainer = base::circular_deque<scoped_refptr<AudioChunk>>;
+ ChunksContainer chunks_;
+ const int bytes_per_sample_;
+
+ DISALLOW_COPY_AND_ASSIGN(AudioBuffer);
+};
+
+} // namespace content
+
+#endif // CONTENT_BROWSER_SPEECH_AUDIO_BUFFER_H_
