Fork VCMDecoderDatabase for VideoReceiver.

This is to keep the deprecated VideoReceiver separate from the
implementation used by VideoReceiver2 before updating
VCMDecoderDatabase to have ownership of the registered decoders.

Fixing typo (DataBase->Database) in the name of the remaining class.

Bug: webrtc:14486, webrtc:14497
Change-Id: I5ee755921454b0831b3af6d0161f5b48c7c60540
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/276781
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38247}
diff --git a/modules/video_coding/video_coding_impl.h b/modules/video_coding/video_coding_impl.h
index 22237ca..927b2da 100644
--- a/modules/video_coding/video_coding_impl.h
+++ b/modules/video_coding/video_coding_impl.h
@@ -11,6 +11,7 @@
 #ifndef MODULES_VIDEO_CODING_VIDEO_CODING_IMPL_H_
 #define MODULES_VIDEO_CODING_VIDEO_CODING_IMPL_H_
 
+#include <map>
 #include <memory>
 #include <string>
 #include <vector>
@@ -18,7 +19,6 @@
 #include "absl/types/optional.h"
 #include "api/field_trials_view.h"
 #include "api/sequence_checker.h"
-#include "modules/video_coding/decoder_database.h"
 #include "modules/video_coding/frame_buffer.h"
 #include "modules/video_coding/generic_decoder.h"
 #include "modules/video_coding/include/video_coding.h"
@@ -55,6 +55,50 @@
   int64_t _latestMs;
 };
 
+class DEPRECATED_VCMDecoderDataBase {
+ public:
+  DEPRECATED_VCMDecoderDataBase();
+  DEPRECATED_VCMDecoderDataBase(const DEPRECATED_VCMDecoderDataBase&) = delete;
+  DEPRECATED_VCMDecoderDataBase& operator=(
+      const DEPRECATED_VCMDecoderDataBase&) = delete;
+  ~DEPRECATED_VCMDecoderDataBase() = default;
+
+  // Returns a pointer to the previously registered decoder or nullptr if none
+  // was registered for the `payload_type`.
+  VideoDecoder* DeregisterExternalDecoder(uint8_t payload_type);
+  void RegisterExternalDecoder(uint8_t payload_type,
+                               VideoDecoder* external_decoder);
+  bool IsExternalDecoderRegistered(uint8_t payload_type) const;
+
+  void RegisterReceiveCodec(uint8_t payload_type,
+                            const VideoDecoder::Settings& settings);
+  bool DeregisterReceiveCodec(uint8_t payload_type);
+
+  // Returns a decoder specified by frame.PayloadType. The decoded frame
+  // callback of the decoder is set to `decoded_frame_callback`. If no such
+  // decoder already exists an instance will be created and initialized.
+  // nullptr is returned if no decoder with the specified payload type was found
+  // and the function failed to create one.
+  VCMGenericDecoder* GetDecoder(
+      const VCMEncodedFrame& frame,
+      VCMDecodedFrameCallback* decoded_frame_callback);
+
+ private:
+  void CreateAndInitDecoder(const VCMEncodedFrame& frame)
+      RTC_RUN_ON(decoder_sequence_checker_);
+
+  SequenceChecker decoder_sequence_checker_;
+
+  absl::optional<uint8_t> current_payload_type_;
+  absl::optional<VCMGenericDecoder> current_decoder_
+      RTC_GUARDED_BY(decoder_sequence_checker_);
+  // Initialization paramaters for decoders keyed by payload type.
+  std::map<uint8_t, VideoDecoder::Settings> decoder_settings_;
+  // Decoders keyed by payload type.
+  std::map<uint8_t, VideoDecoder*> decoders_
+      RTC_GUARDED_BY(decoder_sequence_checker_);
+};
+
 class VideoReceiver {
  public:
   VideoReceiver(Clock* clock,
@@ -122,7 +166,7 @@
   // Callbacks are set before the decoder thread starts.
   // Once the decoder thread has been started, usage of `_codecDataBase` moves
   // over to the decoder thread.
-  VCMDecoderDataBase _codecDataBase;
+  DEPRECATED_VCMDecoderDataBase _codecDataBase;
 
   VCMProcessTimer _retransmissionTimer RTC_GUARDED_BY(module_thread_checker_);
   VCMProcessTimer _keyRequestTimer RTC_GUARDED_BY(module_thread_checker_);