media: Fix gn build for AVDA related files on Android.
media: Fix gn build for AVDA related files on Android.

BUG=507834
TEST=Compiles with "media_use_ffmpeg = true".

Review URL: https://codereview.chromium.org/1421673002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#355412}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk