Split out V4L2 specific code in the Linux Capture backend

This is in preparation for adding a portal / pipewire backend.

This just renames one class and moved the code to different files.
There are no changes to the implementation.

Bug: webrtc:13177
Change-Id: Iae101fcabafdb6cddd4d82adbb26219e4b37557f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/261680
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36848}

modules/video_capture/linux/device_info_v4l2.h

@@ -0,0 +1,51 @@
+/*
+ *  Copyright (c) 2012 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_CAPTURE_LINUX_DEVICE_INFO_V4L2_H_
+#define MODULES_VIDEO_CAPTURE_LINUX_DEVICE_INFO_V4L2_H_
+
+#include <stdint.h>
+
+#include "modules/video_capture/device_info_impl.h"
+
+namespace webrtc {
+namespace videocapturemodule {
+class DeviceInfoV4l2 : public DeviceInfoImpl {
+ public:
+  DeviceInfoV4l2();
+  ~DeviceInfoV4l2() override;
+  uint32_t NumberOfDevices() override;
+  int32_t GetDeviceName(uint32_t deviceNumber,
+                        char* deviceNameUTF8,
+                        uint32_t deviceNameLength,
+                        char* deviceUniqueIdUTF8,
+                        uint32_t deviceUniqueIdUTF8Length,
+                        char* productUniqueIdUTF8 = 0,
+                        uint32_t productUniqueIdUTF8Length = 0) override;
+  /*
+   * Fills the membervariable _captureCapabilities with capabilites for the
+   * given device name.
+   */
+  int32_t CreateCapabilityMap(const char* deviceUniqueIdUTF8) override
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(_apiLock);
+  int32_t DisplayCaptureSettingsDialogBox(const char* /*deviceUniqueIdUTF8*/,
+                                          const char* /*dialogTitleUTF8*/,
+                                          void* /*parentWindow*/,
+                                          uint32_t /*positionX*/,
+                                          uint32_t /*positionY*/) override;
+  int32_t FillCapabilities(int fd) RTC_EXCLUSIVE_LOCKS_REQUIRED(_apiLock);
+  int32_t Init() override;
+
+ private:
+  bool IsDeviceNameMatches(const char* name, const char* deviceUniqueIdUTF8);
+};
+}  // namespace videocapturemodule
+}  // namespace webrtc
+#endif  // MODULES_VIDEO_CAPTURE_LINUX_DEVICE_INFO_V4L2_H_