Move scalability structures from av1 into own subfolder

To make it natural to reuse them for vp9

Bug: webrtc:11999
Change-Id: If2ef7ca16b8be96e0e03bb19211d9f5eb74b2d3d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/188620
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32414}

modules/video_coding/svc/scalability_structure_test_helpers.h

@@ -0,0 +1,52 @@
+/*
+ *  Copyright (c) 2020 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 MODULES_VIDEO_CODING_SVC_SCALABILITY_STRUCTURE_TEST_HELPERS_H_
+#define MODULES_VIDEO_CODING_SVC_SCALABILITY_STRUCTURE_TEST_HELPERS_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "api/transport/rtp/dependency_descriptor.h"
+#include "api/video/video_bitrate_allocation.h"
+#include "common_video/generic_frame_descriptor/generic_frame_info.h"
+#include "modules/video_coding/chain_diff_calculator.h"
+#include "modules/video_coding/frame_dependencies_calculator.h"
+#include "modules/video_coding/svc/scalable_video_controller.h"
+
+namespace webrtc {
+
+// Creates bitrate allocation with non-zero bitrate for given number of temporal
+// layers for each spatial layer.
+VideoBitrateAllocation EnableTemporalLayers(int s0, int s1 = 0, int s2 = 0);
+
+class ScalabilityStructureWrapper {
+ public:
+  explicit ScalabilityStructureWrapper(ScalableVideoController& structure)
+      : structure_controller_(structure) {}
+
+  std::vector<GenericFrameInfo> GenerateFrames(int num_tempral_units,
+                                               bool restart);
+
+  std::vector<GenericFrameInfo> GenerateFrames(int num_temporal_units) {
+    return GenerateFrames(num_temporal_units, /*restart=*/false);
+  }
+
+ private:
+  ScalableVideoController& structure_controller_;
+  std::bitset<8> buffer_contains_frame_ = 0;
+  FrameDependenciesCalculator frame_deps_calculator_;
+  ChainDiffCalculator chain_diff_calculator_;
+  int64_t frame_id_ = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_VIDEO_CODING_SVC_SCALABILITY_STRUCTURE_TEST_HELPERS_H_