Add shuffle support to infinitely looping timeline.

In addition, let unit test assert window indices for both shuffle modes.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=166191069

library/core/src/androidTest/java/com/google/android/exoplayer2/source/LoopingMediaSourceTest.java

@@ -42,44 +42,55 @@ public class LoopingMediaSourceTest extends TestCase {
     Timeline timeline = getLoopingTimeline(multiWindowTimeline, 1);
     TimelineAsserts.assertWindowIds(timeline, 111, 222, 333);
     TimelineAsserts.assertPeriodCounts(timeline, 1, 1, 1);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_OFF, false,
-        C.INDEX_UNSET, 0, 1);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ONE, false, 0, 1, 2);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ALL, false, 2, 0, 1);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_OFF, false,
-        1, 2, C.INDEX_UNSET);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ONE, false, 0, 1, 2);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ALL, false, 1, 2, 0);
+    for (boolean shuffled : new boolean[] { false, true }) {
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_OFF, shuffled,
+          C.INDEX_UNSET, 0, 1);
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ONE, shuffled,
+          0, 1, 2);
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ALL, shuffled,
+          2, 0, 1);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_OFF, shuffled,
+          1, 2, C.INDEX_UNSET);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ONE, shuffled, 0, 1, 2);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ALL, shuffled, 1, 2, 0);
+    }
   }
 
   public void testMultiLoop() {
     Timeline timeline = getLoopingTimeline(multiWindowTimeline, 3);
     TimelineAsserts.assertWindowIds(timeline, 111, 222, 333, 111, 222, 333, 111, 222, 333);
     TimelineAsserts.assertPeriodCounts(timeline, 1, 1, 1, 1, 1, 1, 1, 1, 1);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_OFF, false,
-        C.INDEX_UNSET, 0, 1, 2, 3, 4, 5, 6, 7, 8);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ONE, false,
-        0, 1, 2, 3, 4, 5, 6, 7, 8);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ALL, false,
-        8, 0, 1, 2, 3, 4, 5, 6, 7);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_OFF, false,
-        1, 2, 3, 4, 5, 6, 7, 8, C.INDEX_UNSET);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ONE, false,
-        0, 1, 2, 3, 4, 5, 6, 7, 8);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ALL, false,
-        1, 2, 3, 4, 5, 6, 7, 8, 0);
+    for (boolean shuffled : new boolean[] { false, true }) {
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_OFF, shuffled,
+          C.INDEX_UNSET, 0, 1, 2, 3, 4, 5, 6, 7, 8);
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ONE, shuffled,
+          0, 1, 2, 3, 4, 5, 6, 7, 8);
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ALL, shuffled,
+          8, 0, 1, 2, 3, 4, 5, 6, 7);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_OFF, shuffled,
+          1, 2, 3, 4, 5, 6, 7, 8, C.INDEX_UNSET);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ONE, shuffled,
+          0, 1, 2, 3, 4, 5, 6, 7, 8);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ALL, shuffled,
+          1, 2, 3, 4, 5, 6, 7, 8, 0);
+    }
   }
 
   public void testInfiniteLoop() {
     Timeline timeline = getLoopingTimeline(multiWindowTimeline, Integer.MAX_VALUE);
     TimelineAsserts.assertWindowIds(timeline, 111, 222, 333);
     TimelineAsserts.assertPeriodCounts(timeline, 1, 1, 1);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_OFF, false, 2, 0, 1);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ONE, false, 0, 1, 2);
-    TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ALL, false, 2, 0, 1);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_OFF, false, 1, 2, 0);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ONE, false, 0, 1, 2);
-    TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ALL, false, 1, 2, 0);
+    for (boolean shuffled : new boolean[] { false, true }) {
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_OFF, shuffled,
+          2, 0, 1);
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ONE, shuffled,
+          0, 1, 2);
+      TimelineAsserts.assertPreviousWindowIndices(timeline, Player.REPEAT_MODE_ALL, shuffled,
+          2, 0, 1);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_OFF, shuffled, 1, 2, 0);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ONE, shuffled, 0, 1, 2);
+      TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ALL, shuffled, 1, 2, 0);
+    }
   }
 
   /**
@@ -93,3 +104,4 @@ public class LoopingMediaSourceTest extends TestCase {
   }
 
 }
+

library/core/src/main/java/com/google/android/exoplayer2/source/LoopingMediaSource.java

@@ -171,7 +171,8 @@ public final class LoopingMediaSource implements MediaSource {
         boolean shuffleModeEnabled) {
       int childNextWindowIndex = timeline.getNextWindowIndex(windowIndex, repeatMode,
           shuffleModeEnabled);
-      return childNextWindowIndex == C.INDEX_UNSET ? 0 : childNextWindowIndex;
+      return childNextWindowIndex == C.INDEX_UNSET ? getFirstWindowIndex(shuffleModeEnabled)
+          : childNextWindowIndex;
     }
 
     @Override
@@ -179,7 +180,7 @@ public final class LoopingMediaSource implements MediaSource {
         boolean shuffleModeEnabled) {
       int childPreviousWindowIndex = timeline.getPreviousWindowIndex(windowIndex, repeatMode,
           shuffleModeEnabled);
-      return childPreviousWindowIndex == C.INDEX_UNSET ? getWindowCount() - 1
+      return childPreviousWindowIndex == C.INDEX_UNSET ? getLastWindowIndex(shuffleModeEnabled)
           : childPreviousWindowIndex;
     }