Convert video quality test from a TEST_F to a TEST fixture.

The purpose is to make the fixture reusable in downstream
projects. The CL adds the following things to API:

- api/test/video_quality_test_fixture.h
- api/test/create_video_quality_test_fixture.h

The following things are moved to API:

- call/bitrate_constraints.h (api/bitrate_constraints.h)
- call/simulated_network.h (api/test/simulated_network.h)
- call/media_type.h (api/mediatypes.h)

These are required by the params struct passed to the
fixture. I didn't attempt to split the params struct into
an internal-only and public version in this CL, and as
a result we need to pull in the above things. They are
quite harmless though, so I think it's worth it in order
to avoid splitting up the test config struct.

This CL doesn't solve all the problems we need to
implement downstream tests; we probably need to upstream
tracing variants of FakeNetworkPipe for instance, but
that will come later. This puts in place the basic
structure for now.

Bug: None
Change-Id: I35e26ed126fad27bc7b2a465400291084f6ac911
Reviewed-on: https://webrtc-review.googlesource.com/69601
Commit-Queue: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23714}

api/test/video_quality_test_fixture.h

@@ -0,0 +1,111 @@
+/*
+ *  Copyright (c) 2018 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 API_TEST_VIDEO_QUALITY_TEST_FIXTURE_H_
+#define API_TEST_VIDEO_QUALITY_TEST_FIXTURE_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "api/bitrate_constraints.h"
+#include "api/mediatypes.h"
+#include "api/test/simulated_network.h"
+#include "api/video_codecs/video_encoder_config.h"
+
+namespace webrtc {
+
+class VideoQualityTestFixtureInterface {
+ public:
+  // Parameters are grouped into smaller structs to make it easier to set
+  // the desired elements and skip unused, using aggregate initialization.
+  // Unfortunately, C++11 (as opposed to C11) doesn't support unnamed structs,
+  // which makes the implementation of VideoQualityTest a bit uglier.
+  struct Params {
+    Params();
+    ~Params();
+    struct CallConfig {
+      bool send_side_bwe;
+      BitrateConstraints call_bitrate_config;
+      int num_thumbnails;
+      // Indicates if secondary_(video|ss|screenshare) structures are used.
+      bool dual_video;
+    } call;
+    struct Video {
+      bool enabled;
+      size_t width;
+      size_t height;
+      int32_t fps;
+      int min_bitrate_bps;
+      int target_bitrate_bps;
+      int max_bitrate_bps;
+      bool suspend_below_min_bitrate;
+      std::string codec;
+      int num_temporal_layers;
+      int selected_tl;
+      int min_transmit_bps;
+      bool ulpfec;
+      bool flexfec;
+      bool automatic_scaling;
+      std::string clip_name;  // "Generator" to generate frames instead.
+      size_t capture_device_index;
+    } video[2];
+    struct Audio {
+      bool enabled;
+      bool sync_video;
+      bool dtx;
+    } audio;
+    struct Screenshare {
+      bool enabled;
+      bool generate_slides;
+      int32_t slide_change_interval;
+      int32_t scroll_duration;
+      std::vector<std::string> slides;
+    } screenshare[2];
+    struct Analyzer {
+      std::string test_label;
+      double avg_psnr_threshold;  // (*)
+      double avg_ssim_threshold;  // (*)
+      int test_durations_secs;
+      std::string graph_data_output_filename;
+      std::string graph_title;
+    } analyzer;
+    NetworkSimulationInterface::SimulatedNetworkConfig pipe;
+    struct SS {                          // Spatial scalability.
+      std::vector<VideoStream> streams;  // If empty, one stream is assumed.
+      size_t selected_stream;
+      int num_spatial_layers;
+      int selected_sl;
+      InterLayerPredMode inter_layer_pred;
+      // If empty, bitrates are generated in VP9Impl automatically.
+      std::vector<SpatialLayer> spatial_layers;
+      // If set, default parameters will be used instead of |streams|.
+      bool infer_streams;
+    } ss[2];
+    struct Logging {
+      bool logs;
+      std::string rtc_event_log_name;
+      std::string rtp_dump_name;
+      std::string encoded_frame_base_path;
+    } logging;
+  };
+
+  virtual ~VideoQualityTestFixtureInterface() = default;
+
+  virtual void RunWithAnalyzer(const Params& params) = 0;
+  virtual void RunWithRenderers(const Params& params) = 0;
+
+  virtual const std::map<uint8_t, webrtc::MediaType>& payload_type_map() = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // API_TEST_VIDEO_QUALITY_TEST_FIXTURE_H_