Don't modify playWhenReady in ImaAdsLoader, except for playAd

Store playWhenReady when playAd is called, and restore it if necessary when the
content resumes.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=162471616

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

@@ -143,6 +143,10 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
 
   // Fields tracking the player/loader state.
 
+  /**
+   * Whether the player's play when ready flag has temporarily been set to true for playing ads.
+   */
+  private boolean playWhenReadyOverriddenForAds;
   /**
    * Whether the player is playing an ad.
    */
@@ -243,12 +247,11 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
   }
 
   /**
-   * Detaches any attached player and event listener. To attach a new player, call
+   * Detaches the attached player and event listener. To attach a new player, call
    * {@link #attachPlayer(ExoPlayer, EventListener, ViewGroup)}. Call {@link #release()} to release
    * all resources associated with this instance.
    */
   /* package */ void detachPlayer() {
-    if (player != null) {
     if (adsManager != null && imaPausedContent) {
       adPlaybackState.setAdResumePositionUs(C.msToUs(player.getCurrentPosition()));
       adsManager.pause();
@@ -259,7 +262,6 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
     player = null;
     eventListener = null;
   }
-  }
 
   /**
    * Releases the loader. Must be called when the instance is no longer needed.
@@ -268,9 +270,11 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
     if (adsManager != null) {
       adsManager.destroy();
       adsManager = null;
+      if (player != null) {
         detachPlayer();
       }
     }
+  }
 
   // AdsLoader.AdsLoadedListener implementation.
 
@@ -330,16 +334,12 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
         // After CONTENT_PAUSE_REQUESTED, IMA will playAd/pauseAd/stopAd to show one or more ads
         // before sending CONTENT_RESUME_REQUESTED.
         imaPausedContent = true;
-        if (player != null) {
         pauseContentInternal();
-        }
         break;
       case SKIPPED: // Fall through.
       case CONTENT_RESUME_REQUESTED:
         imaPausedContent = false;
-        if (player != null) {
         resumeContentInternal();
-        }
         break;
       case ALL_ADS_COMPLETED:
         // Do nothing. The ads manager will be released when the source is released.
@@ -425,6 +425,9 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
     if (player == null) {
       // Sometimes messages from IMA arrive after detaching the player. See [Internal: b/63801642].
       Log.w(TAG, "Unexpected playAd while detached");
+    } else if (!player.getPlayWhenReady()) {
+      playWhenReadyOverriddenForAds = true;
+      player.setPlayWhenReady(true);
     }
     if (imaPlayingAd && !imaPausedInAd) {
       // Work around an issue where IMA does not always call stopAd before resuming content.
@@ -432,9 +435,6 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
       Log.w(TAG, "Unexpected playAd without stopAd");
       stopAdInternal();
     }
-    if (player != null) {
-      player.setPlayWhenReady(true);
-    }
     if (!imaPlayingAd) {
       imaPlayingAd = true;
       for (VideoAdPlayerCallback callback : adCallbacks) {
@@ -474,9 +474,6 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
       return;
     }
     imaPausedInAd = true;
-    if (player != null) {
-      player.setPlayWhenReady(false);
-    }
     for (VideoAdPlayerCallback callback : adCallbacks) {
       callback.onPause();
     }
@@ -560,6 +557,10 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
       }
       return;
     }
+    if (!playingAd && playWhenReadyOverriddenForAds) {
+      playWhenReadyOverriddenForAds = false;
+      player.setPlayWhenReady(false);
+    }
     if (!sentContentComplete) {
       boolean adFinished =
           !playingAd || playingAdIndexInAdGroup != player.getCurrentAdIndexInAdGroup();
@@ -571,7 +572,6 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
         }
       }
       if (playingAd && !wasPlayingAd) {
-        player.setPlayWhenReady(false);
         int adGroupIndex = player.getCurrentAdGroupIndex();
         // IMA hasn't sent CONTENT_PAUSE_REQUESTED yet, so fake the content position.
         Assertions.checkState(fakeContentProgressElapsedRealtimeMs == C.TIME_UNSET);
@@ -601,8 +601,7 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
   }
 
   private void resumeContentInternal() {
-    if (contentDurationMs != C.TIME_UNSET) {
+    if (contentDurationMs != C.TIME_UNSET && imaPlayingAd) {
-      if (imaPlayingAd) {
       // Work around an issue where IMA does not always call stopAd before resuming content.
       // See [Internal: b/38354028].
       if (DEBUG) {
@@ -610,8 +609,6 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
       }
       stopAdInternal();
     }
-    }
-    player.setPlayWhenReady(true);
     clearFlags();
   }
 
@@ -623,15 +620,11 @@ public final class ImaAdsLoader implements ExoPlayer.EventListener, VideoAdPlaye
     // IMA is requesting to pause content, so stop faking the content position.
     fakeContentProgressElapsedRealtimeMs = C.TIME_UNSET;
     fakeContentProgressOffsetMs = C.TIME_UNSET;
-    player.setPlayWhenReady(false);
     clearFlags();
   }
 
   private void stopAdInternal() {
     Assertions.checkState(imaPlayingAd);
-    if (player != null) {
-      player.setPlayWhenReady(false);
-    }
     adPlaybackState.playedAd(adGroupIndex);
     updateAdPlaybackState();
     if (!playingAd) {