Simplify (i.e. remove) waiting for first sync frame.

The upstream source (or its stream) should always provide data
starting from a sync frame, so this logic shouldn't be necessary.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=117220759

library/src/main/java/com/google/android/exoplayer/MediaCodecTrackRenderer.java

@@ -228,7 +228,6 @@ public abstract class MediaCodecTrackRenderer extends SampleSourceTrackRenderer
   private boolean inputStreamEnded;
   private boolean outputStreamEnded;
   private boolean waitingForKeys;
-  private boolean waitingForFirstSyncFrame;
 
   /**
    * @param mediaCodecSelector A decoder selector.
@@ -384,7 +383,6 @@ public abstract class MediaCodecTrackRenderer extends SampleSourceTrackRenderer
         SystemClock.elapsedRealtime() : -1;
     inputIndex = -1;
     outputIndex = -1;
-    waitingForFirstSyncFrame = true;
     codecCounters.codecInitCount++;
   }
 
@@ -507,7 +505,6 @@ public abstract class MediaCodecTrackRenderer extends SampleSourceTrackRenderer
     codecHotswapTimeMs = -1;
     inputIndex = -1;
     outputIndex = -1;
-    waitingForFirstSyncFrame = true;
     waitingForKeys = false;
     decodeOnlyPresentationTimestamps.clear();
     if (codecNeedsFlushWorkaround || (codecNeedsEosFlushWorkaround && codecReceivedEos)) {
@@ -628,20 +625,6 @@ public abstract class MediaCodecTrackRenderer extends SampleSourceTrackRenderer
       }
       return false;
     }
-    if (waitingForFirstSyncFrame) {
-      // TODO: Find out if it's possible to supply samples prior to the first sync
-      // frame for HE-AAC.
-      if (!sampleHolder.isSyncFrame()) {
-        sampleHolder.clearData();
-        if (codecReconfigurationState == RECONFIGURATION_STATE_QUEUE_PENDING) {
-          // The buffer we just cleared contained reconfiguration data. We need to re-write this
-          // data into a subsequent buffer (if there is one).
-          codecReconfigurationState = RECONFIGURATION_STATE_WRITE_PENDING;
-        }
-        return true;
-      }
-      waitingForFirstSyncFrame = false;
-    }
     boolean sampleEncrypted = sampleHolder.isEncrypted();
     waitingForKeys = shouldWaitForKeys(sampleEncrypted);
     if (waitingForKeys) {