Use webrtc::EncodedImageBuffer::Create instead of webrtc::EncodedImage::Allocate

The latter is being deprecated in
https://webrtc-review.googlesource.com/c/src/+/155163

A similar use was replaced in cl
https://chromium-review.googlesource.com/c/chromium/src/+/1833466

Bug: webrtc:9378
Change-Id: I7be9f2e79ac303c311cbb252ad8e1e53038b928b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1836496
Auto-Submit: Niels Möller <nisse@chromium.org>
Commit-Queue: Florent Castelli <orphis@chromium.org>
Reviewed-by: Florent Castelli <orphis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702827}

third_party/blink/renderer/platform/peerconnection/rtc_video_encoder.cc

@@ -605,9 +605,9 @@ void RTCVideoEncoder::Impl::BitstreamBufferReady(
   }
 
   webrtc::EncodedImage image;
-  image.Allocate(metadata.payload_size_bytes);
-  image.set_size(metadata.payload_size_bytes);
-  memcpy(image.data(), output_mapping_memory, metadata.payload_size_bytes);
+  image.SetEncodedData(webrtc::EncodedImageBuffer::Create(
+      static_cast<const uint8_t*>(output_mapping_memory),
+      metadata.payload_size_bytes));
   image._encodedWidth = input_visible_size_.width();
   image._encodedHeight = input_visible_size_.height();
   image.SetTimestamp(rtp_timestamp.value());