message: Delete obsolete method EncodedImage::Retain()
  Cr-Commit-Position: refs/heads/master@{#33519}
diff: #include <map>
  #include <utility>
  -#include "absl/base/attributes.h"
  #include "absl/types/optional.h"
  #include "api/rtp_packet_infos.h"
  #include "api/scoped_refptr.h"
  @@ -146,11 +145,6 @@ class RTC_EXPORT EncodedImage {
  return encoded_data_ ? encoded_data_->data() : nullptr;
  }
  - // TODO(bugs.webrtc.org/9378): Obsolete, delete as soon as downstream calls
  - // are fixed.
  - ABSL_DEPRECATED("")
  - void Retain() {}
  -
  uint32_t _encodedWidth = 0;
  uint32_t _encodedHeight = 0;
  // NTP time of the capture time in local timebase in milliseconds.
  