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Two issues are fixed:
- File was somehow muxed into an invalid configuration.
- Not enough was appended to start playback.

Also other tests were flaking, so:
- Increased append size to 128k
- Only start playback after appends complete.
- Mark EOS and add ended listener since append size is small.

BUG=978045
TEST=test passes

Change-Id: I25dc5994044424c53198490d89d3de15f6e5c616
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1680956
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Matthew Wolenetz <wolenetz@chromium.org>
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676165}