[Clank MR] Safely seek in MediaFling to avoid an SDK crash

There was a crash in SDK before version 16.0.2. This CL works around the issue
by generating the low-level message directly.

Bug: 711860
Change-Id: I262143fae845ae6e8d4f9042487f554f7f5d94a1
Reviewed-on: https://chromium-review.googlesource.com/c/1396380
Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Commit-Queue: Zhiqiang Zhang <zqzhang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620125}
3 files changed