Revert r9359 "Implement NetEq's CurrentDelay function"

This reverts commit d8a03facf6986a011c8f889c63d87f9216a1e912, since it
broke the Chrome build. Will have to swap to using base/logging.h in
neteq_impl.cc before re-landing this change.

TBR=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/50219004

Cr-Commit-Position: refs/heads/master@{#9360}

webrtc/modules/audio_coding/neteq/neteq_unittest.cc

@@ -404,8 +404,6 @@ void NetEqDecodingTest::DecodeAndCompare(const std::string& rtp_file,
       ASSERT_EQ(0, neteq_->NetworkStatistics(&network_stats));
       ASSERT_NO_FATAL_FAILURE(
           network_stat_files.ProcessReference(network_stats));
-      // Compare with CurrentDelay, which should be identical.
-      EXPECT_EQ(network_stats.current_buffer_size_ms, neteq_->CurrentDelayMs());
 
       // Process RTCPstat.
       RtcpStatistics rtcp_stats;