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_receiver2.h b/modules/video_coding/video_receiver2.h
index f9b5993..67cb9af 100644
--- a/modules/video_coding/video_receiver2.h
+++ b/modules/video_coding/video_receiver2.h
@@ -63,7 +63,7 @@
   // 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 codec_database_;
+  VCMDecoderDatabase codec_database_;
 };
 
 }  // namespace webrtc