Pass initialization parameters to section readers

Unlike with PesReaders, sections don't have a standard way
of providing timestmaps or even generating tracks. We need
to pass this information so that readers decide what to do
with it.

Issue:#726

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=137162494

library/src/androidTest/java/com/google/android/exoplayer2/extractor/ts/TsExtractorTest.java

@@ -208,6 +208,12 @@ public final class TsExtractorTest extends InstrumentationTestCase {
     private int consumedSdts;
 
     @Override
+    public void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput,
+        TrackIdGenerator idGenerator) {
+      // Do nothing.
+    }
+
+    @Override
     public void consume(ParsableByteArray sectionData) {
       // table_id(8), section_syntax_indicator(1), reserved_future_use(1), reserved(2),
       // section_length(12), transport_stream_id(16), reserved(2), version_number(5),

library/src/main/java/com/google/android/exoplayer2/extractor/ts/SectionPayloadReader.java

@@ -15,6 +15,10 @@
  */
 package com.google.android.exoplayer2.extractor.ts;
 
+import com.google.android.exoplayer2.extractor.ExtractorOutput;
+import com.google.android.exoplayer2.extractor.TimestampAdjuster;
+import com.google.android.exoplayer2.extractor.TrackOutput;
+import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 
 /**
@@ -23,6 +27,17 @@ import com.google.android.exoplayer2.util.ParsableByteArray;
 public interface SectionPayloadReader {
 
   /**
+   * Initializes the section payload reader.
+   *
+   * @param timestampAdjuster A timestamp adjuster for offsetting and scaling sample timestamps.
+   * @param extractorOutput The {@link ExtractorOutput} that receives the extracted data.
+   * @param idGenerator A {@link PesReader.TrackIdGenerator} that generates unique track ids for the
+   *     {@link TrackOutput}s.
+   */
+  void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput,
+      TrackIdGenerator idGenerator);
+
+  /**
    * Called by a {@link SectionReader} when a full section is received.
    *
    * @param sectionData The data belonging to a section, including the section header but excluding

library/src/main/java/com/google/android/exoplayer2/extractor/ts/SectionReader.java

@@ -43,8 +43,7 @@ public final class SectionReader implements TsPayloadReader {
   @Override
   public void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput,
       TrackIdGenerator idGenerator) {
-    // TODO: Injectable section readers might want to generate metadata tracks.
-    // Do nothing.
+    reader.init(timestampAdjuster, extractorOutput, idGenerator);
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer2/extractor/ts/TsExtractor.java

@@ -65,8 +65,6 @@ public final class TsExtractor implements Extractor {
   public static final int TS_STREAM_TYPE_H265 = 0x24;
   public static final int TS_STREAM_TYPE_ID3 = 0x15;
 
-  private static final String TAG = "TsExtractor";
-
   private static final int TS_PACKET_SIZE = 188;
   private static final int TS_SYNC_BYTE = 0x47; // First byte of each TS packet.
   private static final int TS_PAT_PID = 0;
@@ -275,6 +273,12 @@ public final class TsExtractor implements Extractor {
     }
 
     @Override
+    public void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput,
+        TrackIdGenerator idGenerator) {
+      // Do nothing.
+    }
+
+    @Override
     public void consume(ParsableByteArray sectionData) {
       // table_id(8), section_syntax_indicator(1), '0'(1), reserved(2), section_length(12),
       // transport_stream_id (16), reserved (2), version_number (5), current_next_indicator (1),
@@ -317,6 +321,12 @@ public final class TsExtractor implements Extractor {
     }
 
     @Override
+    public void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput,
+        TrackIdGenerator idGenerator) {
+      // Do nothing.
+    }
+
+    @Override
     public void consume(ParsableByteArray sectionData) {
       // table_id(8), section_syntax_indicator(1), '0'(1), reserved(2), section_length(12),
       // program_number (16), reserved (2), version_number (5), current_next_indicator (1),

library/src/main/java/com/google/android/exoplayer2/extractor/ts/TsPayloadReader.java

@@ -99,9 +99,10 @@ public interface TsPayloadReader {
   /**
    * Initializes the payload reader.
    *
-   * @param timestampAdjuster
-   * @param extractorOutput
-   * @param idGenerator
+   * @param timestampAdjuster A timestamp adjuster for offsetting and scaling sample timestamps.
+   * @param extractorOutput The {@link ExtractorOutput} that receives the extracted data.
+   * @param idGenerator A {@link PesReader.TrackIdGenerator} that generates unique track ids for the
+   *     {@link TrackOutput}s.
    */
   void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput,
       TrackIdGenerator idGenerator);