Fix bug in Aes128DataSource

Open was not calling through to upstream.open. This was not problematic for
reading, because DataSourceInputStream.read would open the upstream if it's
not open already. It was however a problem for calling getUri() between
calling open and the first call to read, which would end up calling
upstream.getUri() on the not-yet-opened upstream.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=195689472

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/Aes128DataSource.java

@@ -78,16 +78,19 @@ import javax.crypto.spec.SecretKeySpec;
       throw new RuntimeException(e);
     }
 
-    cipherInputStream = new CipherInputStream(
-        new DataSourceInputStream(upstream, dataSpec), cipher);
+    DataSourceInputStream inputStream = new DataSourceInputStream(upstream, dataSpec);
+    cipherInputStream = new CipherInputStream(inputStream, cipher);
+    inputStream.open();
 
     return C.LENGTH_UNSET;
   }
 
   @Override
   public void close() throws IOException {
-    cipherInputStream = null;
-    upstream.close();
+    if (cipherInputStream != null) {
+      cipherInputStream = null;
+      upstream.close();
+    }
   }
 
   @Override

library/hls/src/test/java/com/google/android/exoplayer2/source/hls/Aes128DataSourceTest.java

@@ -0,0 +1,101 @@
+/*
+ * 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.source.hls;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.net.Uri;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.upstream.DataSource;
+import com.google.android.exoplayer2.upstream.DataSpec;
+import java.io.IOException;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Test for {@link Aes128DataSource}. */
+@RunWith(RobolectricTestRunner.class)
+public class Aes128DataSourceTest {
+
+  @Test
+  public void test_OpenCallsUpstreamOpen_CloseCallsUpstreamClose() throws IOException {
+    UpstreamDataSource upstream = new UpstreamDataSource();
+    Aes128DataSource testInstance = new Aes128DataSource(upstream, new byte[16], new byte[16]);
+    assertThat(upstream.opened).isFalse();
+
+    Uri uri = Uri.parse("http.abc.com/def");
+    testInstance.open(new DataSpec(uri));
+    assertThat(upstream.opened).isTrue();
+
+    testInstance.close();
+    assertThat(upstream.opened).isFalse();
+  }
+
+  @Test
+  public void test_OpenCallsUpstreamThrowingOpen_CloseCallsUpstreamClose() throws IOException {
+    UpstreamDataSource upstream =
+        new UpstreamDataSource() {
+          @Override
+          public long open(DataSpec dataSpec) throws IOException {
+            throw new IOException();
+          }
+        };
+    Aes128DataSource testInstance = new Aes128DataSource(upstream, new byte[16], new byte[16]);
+    assertThat(upstream.opened).isFalse();
+
+    Uri uri = Uri.parse("http.abc.com/def");
+    try {
+      testInstance.open(new DataSpec(uri));
+    } catch (IOException e) {
+      // Expected.
+    }
+    assertThat(upstream.opened).isFalse();
+    assertThat(upstream.closedCalled).isFalse();
+
+    // Even though the upstream open call failed, close should still call close on the upstream as
+    // per the contract of DataSource.
+    testInstance.close();
+    assertThat(upstream.closedCalled).isTrue();
+  }
+
+  private static class UpstreamDataSource implements DataSource {
+
+    public boolean opened;
+    public boolean closedCalled;
+
+    @Override
+    public long open(DataSpec dataSpec) throws IOException {
+      opened = true;
+      return C.LENGTH_UNSET;
+    }
+
+    @Override
+    public int read(byte[] buffer, int offset, int readLength) {
+      return C.RESULT_END_OF_INPUT;
+    }
+
+    @Override
+    public Uri getUri() {
+      return null;
+    }
+
+    @Override
+    public void close() {
+      opened = false;
+      closedCalled = true;
+    }
+  }
+}