BandwidthMeter shouldn't extend TransferListener

There may be other ways to estimate bandwidth that don't
require listening to our own transfers.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127741651

demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -53,7 +53,6 @@ import com.google.android.exoplayer2.trackselection.MappingTrackSelector.TrackIn
 import com.google.android.exoplayer2.ui.AspectRatioFrameLayout;
 import com.google.android.exoplayer2.ui.DebugTextViewHelper;
 import com.google.android.exoplayer2.ui.PlayerControl;
-import com.google.android.exoplayer2.upstream.BandwidthMeter;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DefaultBandwidthMeter;
 import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;
@@ -152,7 +151,7 @@ public class PlayerActivity extends Activity implements SurfaceHolder.Callback,
     super.onCreate(savedInstanceState);
     String userAgent = Util.getUserAgent(this, "ExoPlayerDemo");
     manifestDataSourceFactory = new DefaultDataSourceFactory(this, userAgent);
-    BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
+    DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
     mediaDataSourceFactory = new DefaultDataSourceFactory(this, userAgent, bandwidthMeter);
     formatEvaluatorFactory = new AdaptiveEvaluator.Factory(bandwidthMeter);
 

library/src/main/java/com/google/android/exoplayer2/upstream/BandwidthMeter.java

@@ -18,7 +18,7 @@ package com.google.android.exoplayer2.upstream;
 /**
  * Provides estimates of the currently available bandwidth.
  */
-public interface BandwidthMeter extends TransferListener {
+public interface BandwidthMeter {
 
   /**
    * Interface definition for a callback to be notified of {@link BandwidthMeter} events.

library/src/main/java/com/google/android/exoplayer2/upstream/DefaultBandwidthMeter.java

@@ -25,7 +25,7 @@ import android.os.SystemClock;
  * Counts transferred bytes while transfers are open and creates a bandwidth sample and updated
  * bandwidth estimate each time a transfer ends.
  */
-public final class DefaultBandwidthMeter implements BandwidthMeter {
+public final class DefaultBandwidthMeter implements BandwidthMeter, TransferListener {
 
   public static final int DEFAULT_MAX_WEIGHT = 2000;
 

playbacktests/src/main/java/com/google/android/exoplayer2/playbacktests/gts/DashTest.java

@@ -37,7 +37,6 @@ import com.google.android.exoplayer2.source.dash.DashMediaSource;
 import com.google.android.exoplayer2.source.dash.DefaultDashChunkSource;
 import com.google.android.exoplayer2.trackselection.MappingTrackSelector;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
-import com.google.android.exoplayer2.upstream.BandwidthMeter;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DefaultBandwidthMeter;
 import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;
@@ -425,7 +424,7 @@ public final class DashTest extends ActivityInstrumentationTestCase2<HostActivit
     @Override
     public MediaSource buildSource(HostActivity host, String userAgent) {
       DataSource.Factory manifestDataSourceFactory = new DefaultDataSourceFactory(host, userAgent);
-      BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
+      DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
       DataSource.Factory mediaDataSourceFactory = new DefaultDataSourceFactory(host, userAgent,
           bandwidthMeter);
       FormatEvaluator.Factory formatEvaluatorFactory = new AdaptiveEvaluator.Factory(