Clean up player event handling

This change is similar to e8293b92
but without relying on new player events that haven't been released
yet, to make it easier to merge changes related to ImaAdsLoader on
top.

extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java

@@ -332,7 +332,7 @@ public final class ImaAdsLoader
   private VideoProgressUpdate lastAdProgress;
   private VideoProgressUpdate lastAdProgress;
   private int lastVolumePercentage;
   private int lastVolumePercentage;
 
 
-  private AdsManager adsManager;
+  @Nullable private AdsManager adsManager;
   private boolean initializedAdsManager;
   private boolean initializedAdsManager;
   private AdLoadException pendingAdLoadError;
   private AdLoadException pendingAdLoadError;
   private Timeline timeline;
   private Timeline timeline;
@@ -975,12 +975,12 @@ public final class ImaAdsLoader
       initializedAdsManager = true;
       initializedAdsManager = true;
       initializeAdsManager();
       initializeAdsManager();
     }
     }
-    onPositionDiscontinuity(Player.DISCONTINUITY_REASON_INTERNAL);
+    checkForContentCompleteOrNewAdGroup();
   }
   }
 
 
   @Override
   @Override
   public void onPlayerStateChanged(boolean playWhenReady, @Player.State int playbackState) {
   public void onPlayerStateChanged(boolean playWhenReady, @Player.State int playbackState) {
-    if (adsManager == null) {
+    if (adsManager == null || player == null) {
       return;
       return;
     }
     }
 
 
@@ -993,18 +993,7 @@ public final class ImaAdsLoader
       adsManager.resume();
       adsManager.resume();
       return;
       return;
     }
     }
-
-    if (imaAdState == IMA_AD_STATE_NONE && playbackState == Player.STATE_BUFFERING
-        && playWhenReady) {
-      checkForContentComplete();
-    } else if (imaAdState != IMA_AD_STATE_NONE && playbackState == Player.STATE_ENDED) {
-      for (int i = 0; i < adCallbacks.size(); i++) {
-        adCallbacks.get(i).onEnded();
-      }
-      if (DEBUG) {
-        Log.d(TAG, "VideoAdPlayerCallback.onEnded in onPlayerStateChanged");
-      }
-    }
+    handlePlayerStateChanged(playWhenReady, playbackState);
   }
   }
 
 
   @Override
   @Override
@@ -1018,32 +1007,7 @@ public final class ImaAdsLoader
 
 
   @Override
   @Override
   public void onPositionDiscontinuity(@Player.DiscontinuityReason int reason) {
   public void onPositionDiscontinuity(@Player.DiscontinuityReason int reason) {
-    if (adsManager == null) {
-      return;
-    }
-    if (!playingAd && !player.isPlayingAd()) {
-      checkForContentComplete();
-      if (sentContentComplete) {
-        for (int i = 0; i < adPlaybackState.adGroupCount; i++) {
-          if (adPlaybackState.adGroupTimesUs[i] != C.TIME_END_OF_SOURCE) {
-            adPlaybackState = adPlaybackState.withSkippedAdGroup(i);
-          }
-        }
-        updateAdPlaybackState();
-      } else if (!timeline.isEmpty()) {
-        long positionMs = player.getCurrentPosition();
-        timeline.getPeriod(0, period);
-        int newAdGroupIndex = period.getAdGroupIndexForPositionUs(C.msToUs(positionMs));
-        if (newAdGroupIndex != C.INDEX_UNSET) {
-          sentPendingContentPositionMs = false;
-          pendingContentPositionMs = positionMs;
-          if (newAdGroupIndex != adGroupIndex) {
-            shouldNotifyAdPrepareError = false;
-          }
-        }
-      }
-    }
-    updateImaStateForPlayerState();
+    checkForContentCompleteOrNewAdGroup();
   }
   }
 
 
   // Internal methods.
   // Internal methods.
@@ -1176,6 +1140,50 @@ public final class ImaAdsLoader
     }
     }
   }
   }
 
 
+  private void handlePlayerStateChanged(boolean playWhenReady, @Player.State int playbackState) {
+    if (imaAdState == IMA_AD_STATE_NONE
+        && playbackState == Player.STATE_BUFFERING
+        && playWhenReady) {
+      checkForContentComplete();
+    } else if (imaAdState != IMA_AD_STATE_NONE && playbackState == Player.STATE_ENDED) {
+      for (int i = 0; i < adCallbacks.size(); i++) {
+        adCallbacks.get(i).onEnded();
+      }
+      if (DEBUG) {
+        Log.d(TAG, "VideoAdPlayerCallback.onEnded in onPlayerStateChanged");
+      }
+    }
+  }
+
+  private void checkForContentCompleteOrNewAdGroup() {
+    if (adsManager == null || player == null) {
+      return;
+    }
+    if (!playingAd && !player.isPlayingAd()) {
+      checkForContentComplete();
+      if (sentContentComplete) {
+        for (int i = 0; i < adPlaybackState.adGroupCount; i++) {
+          if (adPlaybackState.adGroupTimesUs[i] != C.TIME_END_OF_SOURCE) {
+            adPlaybackState = adPlaybackState.withSkippedAdGroup(/* adGroupIndex= */ i);
+          }
+        }
+        updateAdPlaybackState();
+      } else if (!timeline.isEmpty()) {
+        long positionMs = player.getCurrentPosition();
+        timeline.getPeriod(/* periodIndex= */ 0, period);
+        int newAdGroupIndex = period.getAdGroupIndexForPositionUs(C.msToUs(positionMs));
+        if (newAdGroupIndex != C.INDEX_UNSET) {
+          sentPendingContentPositionMs = false;
+          pendingContentPositionMs = positionMs;
+          if (newAdGroupIndex != adGroupIndex) {
+            shouldNotifyAdPrepareError = false;
+          }
+        }
+      }
+    }
+    updateImaStateForPlayerState();
+  }
+
   private void updateImaStateForPlayerState() {
   private void updateImaStateForPlayerState() {
     boolean wasPlayingAd = playingAd;
     boolean wasPlayingAd = playingAd;
     int oldPlayingAdIndexInAdGroup = playingAdIndexInAdGroup;
     int oldPlayingAdIndexInAdGroup = playingAdIndexInAdGroup;