message: Add default implementation of deprecated StartAecDump method.
  Intended to enable deletion in downstream mock classes.
  Tbr:
  Cr-Commit-Position: refs/heads/master@{#28318}
diff: @@ -1413,7 +1413,9 @@ class PeerConnectionFactoryInterface : public rtc::RefCountInterface {
  return false;
  }
  // TODO(webrtc:6463): Deprecated; PlatformFile will soon be deleted.
  - virtual bool StartAecDump(rtc::PlatformFile file, int64_t max_size_bytes) = 0;
  + virtual bool StartAecDump(rtc::PlatformFile file, int64_t max_size_bytes) {
  + return false;
  + }
  // Stops logging the AEC dump.
  virtual void StopAecDump() = 0;
  