Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/frame_blocker.h

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_FRAME_BLOCKER_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_FRAME_BLOCKER_H_
+
+#include <stddef.h>
+#include <vector>
+
+#include "webrtc/base/array_view.h"
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
+
+namespace webrtc {
+
+// Class for producing 64 sample multiband blocks from frames consisting of 1 or
+// 2 subframes of 80 samples.
+class FrameBlocker {
+ public:
+  explicit FrameBlocker(size_t num_bands);
+  ~FrameBlocker();
+  // Inserts one 80 sample multiband subframe from the multiband frame and
+  // extracts one 64 sample multiband block.
+  void InsertSubFrameAndExtractBlock(
+      const std::vector<rtc::ArrayView<float>>& sub_frame,
+      std::vector<std::vector<float>>* block);
+  // Reports whether a multiband block of 64 samples is available for
+  // extraction.
+  bool IsBlockAvailable() const;
+  // Extracts a multiband block of 64 samples.
+  void ExtractBlock(std::vector<std::vector<float>>* block);
+
+ private:
+  const size_t num_bands_;
+  std::vector<std::vector<float>> buffer_;
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(FrameBlocker);
+};
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_FRAME_BLOCKER_H_