Extend components/test_runner's generated WebMediaStream to have a ChromeMock VideoTrack and Source

components/test_runner/renderer/mock_video_capturer_source.h

Index: components/test_runner/renderer/mock_video_capturer_source.h
diff --git a/components/test_runner/renderer/mock_video_capturer_source.h b/components/test_runner/renderer/mock_video_capturer_source.h
new file mode 100644
index 0000000000000000000000000000000000000000..58e75737e1accf13a4c3a20480b0fbae054d040a
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+++ b/components/test_runner/renderer/mock_video_capturer_source.h
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+// Copyright 2015 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 COMPONENTS_TEST_RUNNER_CONTENT_RENDERER_MOCK_VIDEO_CAPTURER_SOURCE_H_
+#define COMPONENTS_TEST_RUNNER_CONTENT_RENDERER_MOCK_VIDEO_CAPTURER_SOURCE_H_
+
+#include "content/public/renderer/media_stream_api.h"
+
+namespace test_runner {
+
+class MockVideoCapturerSource : public media::VideoCapturerSource {
+ public:
+  MockVideoCapturerSource() = default;
+  ~MockVideoCapturerSource() override {}
+
+  void GetCurrentSupportedFormats(
+      int max_requested_width,
+      int max_requested_height,
+      double max_requested_frame_rate,
+      const VideoCaptureDeviceFormatsCB& callback) override {}
+  void StartCapture(
+      const media::VideoCaptureParams& params,
+      const VideoCaptureDeliverFrameCB& new_frame_callback,
+      const RunningCallback& running_callback) override {}
+  void StopCapture() override {}
+};
+
+}  // namespace test_runner
+
+#endif  // COMPONENTS_TEST_RUNNER_CONTENT_RENDERER_MOCK_VIDEO_CAPTURER_SOURCE_H_