Add Downloader.getCounters method

PiperOrigin-RevId: 241636860

library/core/src/main/java/com/google/android/exoplayer2/offline/Downloader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.offline;
 
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.upstream.cache.CacheUtil.CachingCounters;
 import java.io.IOException;
 
 /**
@@ -47,6 +48,9 @@ public interface Downloader {
    */
   float getDownloadPercentage();
 
+  /** Returns a {@link CachingCounters} which holds download counters. */
+  CachingCounters getCounters();
+
   /**
    * Removes the media.
    *

library/core/src/main/java/com/google/android/exoplayer2/offline/ProgressiveDownloader.java

@@ -107,6 +107,11 @@ public final class ProgressiveDownloader implements Downloader {
   }
 
   @Override
+  public CachingCounters getCounters() {
+    return cachingCounters;
+  }
+
+  @Override
   public void remove() {
     CacheUtil.remove(dataSpec, cache, cacheKeyFactory);
   }

library/core/src/main/java/com/google/android/exoplayer2/offline/SegmentDownloader.java

@@ -159,6 +159,11 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
   }
 
   @Override
+  public CachingCounters getCounters() {
+    return counters;
+  }
+
+  @Override
   public final void remove() throws InterruptedException {
     try {
       M manifest = getManifest(offlineDataSource, manifestDataSpec);

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadManagerTest.java

@@ -28,6 +28,7 @@ import com.google.android.exoplayer2.testutil.DummyMainThread.TestRunnable;
 import com.google.android.exoplayer2.testutil.RobolectricUtil;
 import com.google.android.exoplayer2.testutil.TestDownloadManagerListener;
 import com.google.android.exoplayer2.testutil.TestUtil;
+import com.google.android.exoplayer2.upstream.cache.CacheUtil.CachingCounters;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -747,6 +748,11 @@ public class DownloadManagerTest {
       return C.PERCENTAGE_UNSET;
     }
 
+    @Override
+    public CachingCounters getCounters() {
+      return null;
+    }
+
     private void assertDoesNotStart() throws InterruptedException {
       Thread.sleep(ASSERT_FALSE_TIME);
       assertThat(started.getCount()).isEqualTo(1);