Add DummyExtractorOutput

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=209417004

library/core/src/main/java/com/google/android/exoplayer2/extractor/DummyExtractorOutput.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2018 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.extractor;
+
+/** A dummy {@link ExtractorOutput} implementation. */
+public final class DummyExtractorOutput implements ExtractorOutput {
+
+  @Override
+  public TrackOutput track(int id, int type) {
+    return new DummyTrackOutput();
+  }
+
+  @Override
+  public void endTracks() {
+    // Do nothing.
+  }
+
+  @Override
+  public void seekMap(SeekMap seekMap) {
+    // Do nothing.
+  }
+}