Decouple HlsSampleStream from HlsSampleStreamWrapper

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=131731376

library/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStream.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.source.hls;
+
+import com.google.android.exoplayer2.FormatHolder;
+import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
+import com.google.android.exoplayer2.source.SampleStream;
+import java.io.IOException;
+
+/**
+ * {@link SampleStream} for a particular track group in HLS.
+ */
+/* package */ final class HlsSampleStream implements SampleStream {
+
+  public final int group;
+  
+  private final HlsSampleStreamWrapper sampleStreamWrapper;
+
+  public HlsSampleStream(HlsSampleStreamWrapper sampleStreamWrapper, int group) {
+    this.sampleStreamWrapper = sampleStreamWrapper;
+    this.group = group;
+  }
+
+  @Override
+  public boolean isReady() {
+    return sampleStreamWrapper.isReady(group);
+  }
+
+  @Override
+  public void maybeThrowError() throws IOException {
+    sampleStreamWrapper.maybeThrowError();
+  }
+
+  @Override
+  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
+    return sampleStreamWrapper.readData(group, formatHolder, buffer);
+  }
+
+  @Override
+  public void skipToKeyframeBefore(long timeUs) {
+    sampleStreamWrapper.skipToKeyframeBefore(group, timeUs);
+  }
+
+}

library/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java

@@ -154,7 +154,7 @@ import java.util.LinkedList;
     // Disable old tracks.
     for (int i = 0; i < selections.length; i++) {
       if (streams[i] != null && (selections[i] == null || !mayRetainStreamFlags[i])) {
-        int group = ((SampleStreamImpl) streams[i]).group;
+        int group = ((HlsSampleStream) streams[i]).group;
         setTrackGroupEnabledState(group, false);
         sampleQueues.valueAt(group).disable();
         streams[i] = null;
@@ -170,7 +170,7 @@ import java.util.LinkedList;
         if (group == primaryTrackGroupIndex) {
           chunkSource.selectTracks(selection);
         }
-        streams[i] = new SampleStreamImpl(group);
+        streams[i] = new HlsSampleStream(this, group);
         streamResetFlags[i] = true;
         selectedNewTracks = true;
       }
@@ -283,6 +283,10 @@ import java.util.LinkedList;
         lastSeekPositionUs);
   }
 
+  /* package */ void skipToKeyframeBefore(int group, long timeUs) {
+    sampleQueues.valueAt(group).skipToKeyframeBefore(timeUs);
+  }
+
   private boolean finishedReadingChunk(HlsMediaChunk chunk) {
     int chunkUid = chunk.uid;
     for (int i = 0; i < sampleQueues.size(); i++) {
@@ -600,34 +604,4 @@ import java.util.LinkedList;
     return pendingResetPositionUs != C.TIME_UNSET;
   }
 
-  private final class SampleStreamImpl implements SampleStream {
-
-    private final int group;
-
-    public SampleStreamImpl(int group) {
-      this.group = group;
-    }
-
-    @Override
-    public boolean isReady() {
-      return HlsSampleStreamWrapper.this.isReady(group);
-    }
-
-    @Override
-    public void maybeThrowError() throws IOException {
-      HlsSampleStreamWrapper.this.maybeThrowError();
-    }
-
-    @Override
-    public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
-      return HlsSampleStreamWrapper.this.readData(group, formatHolder, buffer);
-    }
-
-    @Override
-    public void skipToKeyframeBefore(long timeUs) {
-      sampleQueues.valueAt(group).skipToKeyframeBefore(timeUs);
-    }
-
-  }
-
 }