Add powerEfficientDecoder and powerEfficientEncoder stats

The spec for these are at https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-powerefficientdecoder and https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-powerefficientdecoder

These stats are based on the is_hardware_accelerated boolean in both the
DecoderInfo and EncoderInfo structs.

Bug: webrtc:14483
Change-Id: I4610da3c6ae977f5853a3b3424d91d864fe72592
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/274409
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Evan Shrubsole <eshr@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38441}

modules/video_coding/generic_decoder.h

@@ -63,7 +63,7 @@ class VCMDecodedFrameCallback : public DecodedImageCallback {
                absl::optional<int32_t> decode_time_ms,
                absl::optional<uint8_t> qp) override;
 
-  void OnDecoderImplementationName(const char* implementation_name);
+  void OnDecoderInfoChanged(const VideoDecoder::DecoderInfo& decoder_info);
 
   void Map(FrameInfo frameInfo);
   void ClearTimestampMap();