Refactor VideoTrackRecorder into smaller classes

content/renderer/BUILD.gn

Index: content/renderer/BUILD.gn
diff --git a/content/renderer/BUILD.gn b/content/renderer/BUILD.gn
index 19de47d2612c0c21f77139d04e6430e67326c847..0b9e9478a15651ddcd019e22a9653582888607f8 100644
--- a/content/renderer/BUILD.gn
+++ b/content/renderer/BUILD.gn
@@ -690,8 +690,12 @@ target(link_target_type, "renderer") {
       "media_recorder/audio_track_recorder.h",
       "media_recorder/media_recorder_handler.cc",
       "media_recorder/media_recorder_handler.h",
+      "media_recorder/vea_encoder.cc",
+      "media_recorder/vea_encoder.h",
       "media_recorder/video_track_recorder.cc",
       "media_recorder/video_track_recorder.h",
+      "media_recorder/vpx_encoder.cc",
+      "media_recorder/vpx_encoder.h",
       "p2p/empty_network_manager.cc",
       "p2p/empty_network_manager.h",
       "p2p/filtering_network_manager.cc",
@@ -753,6 +757,10 @@ target(link_target_type, "renderer") {
       "//third_party/webrtc_overrides:init_webrtc",
     ]
     if (rtc_use_h264) {
+      sources += [
+        "media_recorder/h264_encoder.cc",
+        "media_recorder/h264_encoder.h",
+      ]
       deps += [ "//third_party/openh264:encoder" ]
     }
   } else {