Reset DefaultBandwidthMeter on network type change

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=219454931

library/core/src/main/java/com/google/android/exoplayer2/util/SlidingPercentile.java

@@ -65,6 +65,14 @@ public class SlidingPercentile {
     currentSortOrder = SORT_ORDER_NONE;
   }
 
+  /** Resets the sliding percentile. */
+  public void reset() {
+    samples.clear();
+    currentSortOrder = SORT_ORDER_NONE;
+    nextSampleIndex = 0;
+    totalWeight = 0;
+  }
+
   /**
    * Adds a new weighted value.
    *

library/core/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -1652,7 +1652,7 @@ public final class Util {
         return getMobileNetworkType(networkInfo);
       case ConnectivityManager.TYPE_ETHERNET:
         return C.NETWORK_TYPE_ETHERNET;
-      default: // Ethernet, VPN, Bluetooth, Dummy.
+      default: // VPN, Bluetooth, Dummy.
         return C.NETWORK_TYPE_OTHER;
     }
   }

library/core/src/test/java/com/google/android/exoplayer2/upstream/DefaultBandwidthMeterTest.java

@@ -15,15 +15,18 @@
  */
 package com.google.android.exoplayer2.upstream;
 
-import static android.Manifest.permission.ACCESS_NETWORK_STATE;
 import static com.google.common.truth.Truth.assertThat;
 
 import android.content.Context;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 import android.net.NetworkInfo.DetailedState;
+import android.net.Uri;
 import android.telephony.TelephonyManager;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.testutil.FakeClock;
+import com.google.android.exoplayer2.testutil.FakeDataSource;
+import java.util.Random;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -36,6 +39,7 @@ import org.robolectric.shadows.ShadowNetworkInfo;
 @RunWith(RobolectricTestRunner.class)
 public final class DefaultBandwidthMeterTest {
 
+  private static final int SIMULATED_TRANSFER_COUNT = 100;
   private static final String FAST_COUNTRY_ISO = "EE";
   private static final String SLOW_COUNTRY_ISO = "PG";
 
@@ -496,6 +500,44 @@ public final class DefaultBandwidthMeterTest {
   }
 
   @Test
+  public void networkTypeOverride_updatesBitrateEstimate() {
+    setActiveNetworkInfo(networkInfoEthernet);
+    DefaultBandwidthMeter bandwidthMeter =
+        new DefaultBandwidthMeter.Builder(RuntimeEnvironment.application).build();
+    long initialEstimateEthernet = bandwidthMeter.getBitrateEstimate();
+
+    bandwidthMeter.setNetworkTypeOverride(C.NETWORK_TYPE_2G);
+    long initialEstimate2g = bandwidthMeter.getBitrateEstimate();
+
+    assertThat(initialEstimateEthernet).isGreaterThan(initialEstimate2g);
+  }
+
+  @Test
+  public void networkTypeOverride_doesFullReset() {
+    // Simulate transfers for an ethernet connection.
+    setActiveNetworkInfo(networkInfoEthernet);
+    FakeClock clock = new FakeClock(/* initialTimeMs= */ 0);
+    DefaultBandwidthMeter bandwidthMeter =
+        new DefaultBandwidthMeter.Builder(RuntimeEnvironment.application).setClock(clock).build();
+    long[] bitrateEstimatesWithNewInstance = simulateTransfers(bandwidthMeter, clock);
+
+    // Create a new instance and seed with some transfers.
+    setActiveNetworkInfo(networkInfo2g);
+    bandwidthMeter =
+        new DefaultBandwidthMeter.Builder(RuntimeEnvironment.application).setClock(clock).build();
+    simulateTransfers(bandwidthMeter, clock);
+
+    // Override the network type to ethernet and simulate transfers again.
+    bandwidthMeter.setNetworkTypeOverride(C.NETWORK_TYPE_ETHERNET);
+    long[] bitrateEstimatesAfterReset = simulateTransfers(bandwidthMeter, clock);
+
+    // If overriding the network type fully reset the bandwidth meter, we expect the bitrate
+    // estimates generated during simulation to be the same.
+    assertThat(bitrateEstimatesAfterReset).isEqualTo(bitrateEstimatesWithNewInstance);
+  }
+
+  @Test
+  @SuppressWarnings("deprecation")
   public void defaultInitialBitrateEstimate_withoutContext_isReasonable() {
     DefaultBandwidthMeter bandwidthMeterWithBuilder =
         new DefaultBandwidthMeter.Builder(/* context= */ null).build();
@@ -510,17 +552,6 @@ public final class DefaultBandwidthMeterTest {
     assertThat(initialEstimateWithoutBuilder).isLessThan(50_000_000L);
   }
 
-  @Test
-  public void defaultInitialBitrateEstimate_withoutAccessNetworkStatePermission_isReasonable() {
-    Shadows.shadowOf(RuntimeEnvironment.application).denyPermissions(ACCESS_NETWORK_STATE);
-    DefaultBandwidthMeter bandwidthMeter =
-        new DefaultBandwidthMeter.Builder(RuntimeEnvironment.application).build();
-    long initialEstimate = bandwidthMeter.getBitrateEstimate();
-
-    assertThat(initialEstimate).isGreaterThan(100_000L);
-    assertThat(initialEstimate).isLessThan(50_000_000L);
-  }
-
   private void setActiveNetworkInfo(NetworkInfo networkInfo) {
     Shadows.shadowOf(connectivityManager).setActiveNetworkInfo(networkInfo);
   }
@@ -528,4 +559,23 @@ public final class DefaultBandwidthMeterTest {
   private void setNetworkCountryIso(String countryIso) {
     Shadows.shadowOf(telephonyManager).setNetworkCountryIso(countryIso);
   }
+
+  private static long[] simulateTransfers(DefaultBandwidthMeter bandwidthMeter, FakeClock clock) {
+    long[] bitrateEstimates = new long[SIMULATED_TRANSFER_COUNT];
+    Random random = new Random(/* seed= */ 0);
+    DataSource dataSource = new FakeDataSource();
+    DataSpec dataSpec = new DataSpec(Uri.parse("https://dummy.com"));
+    for (int i = 0; i < SIMULATED_TRANSFER_COUNT; i++) {
+      bandwidthMeter.onTransferStart(dataSource, dataSpec, /* isNetwork= */ true);
+      clock.advanceTime(random.nextInt(/* bound= */ 5000));
+      bandwidthMeter.onBytesTransferred(
+          dataSource,
+          dataSpec,
+          /* isNetwork= */ true,
+          /* bytes= */ random.nextInt(5 * 1024 * 1024));
+      bandwidthMeter.onTransferEnd(dataSource, dataSpec, /* isNetwork= */ true);
+      bitrateEstimates[i] = bandwidthMeter.getBitrateEstimate();
+    }
+    return bitrateEstimates;
+  }
 }