SDK / exoplayer

There are 4 tests which can't currently be moved:
 - DownloadManagerTest explicitly uses the main looper which isn't easily
   supported because the test runs on this thread.
 - ContentDataSourceTest uses an AssetFileDescriptor which wraps a
   ParcelFileDescriptor. It seems Robolectric doesn't correctly forward the
   inner wrapped file descriptor leading to NPE.
 - CacheContentIndexTest and SimpleCacheSpanTest both work fine with Gradle
   but fail with seemingly valid test failures on Blaze.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=185366678