The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3ef42f4500b1e5c8581822b84a311303dae6e75b

commit 3ef42f4500b1e5c8581822b84a311303dae6e75b
Author: Shuhei Takahashi <nya@chromium.org>
Date: Thu Sep 21 09:46:37 2017

recent: Remove audio_root from ARC media source.

audio_root does not support recent document queries. Querying
it will leave a noisy stack trace in Android logcat.

BUG= chromium:767345 
TEST=No stack trace in Android logcat

Change-Id: Ia12dfa4c96fd33877f1b5d80c390c53dece0a219
Reviewed-on: https://chromium-review.googlesource.com/676829
Reviewed-by: Tomasz Mikolajewski <mtomasz@chromium.org>
Commit-Queue: Shuhei Takahashi <nya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503403}
[modify] https://crrev.com/3ef42f4500b1e5c8581822b84a311303dae6e75b/chrome/browser/chromeos/fileapi/recent_arc_media_source.cc

This is very low-risk one-line fix, so I'm requesting M-62 merge.

Without this patch, Android crash report is uploaded every time the user opens Recent root in Files app, which is quite noisy and not good for user's network bandwidth.

Approved for 62. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/46978193dcf59550857db0d32caf29beb3513605

commit 46978193dcf59550857db0d32caf29beb3513605
Author: Shuhei Takahashi <nya@chromium.org>
Date: Fri Sep 22 04:24:51 2017

recent: Remove audio_root from ARC media source.

audio_root does not support recent document queries. Querying
it will leave a noisy stack trace in Android logcat.

BUG= chromium:767345 
TEST=No stack trace in Android logcat
TBR=nya@chromium.org

(cherry picked from commit 3ef42f4500b1e5c8581822b84a311303dae6e75b)

Change-Id: Ia12dfa4c96fd33877f1b5d80c390c53dece0a219
Reviewed-on: https://chromium-review.googlesource.com/676829
Reviewed-by: Tomasz Mikolajewski <mtomasz@chromium.org>
Commit-Queue: Shuhei Takahashi <nya@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#503403}
Reviewed-on: https://chromium-review.googlesource.com/678414
Reviewed-by: Shuhei Takahashi <nya@chromium.org>
Cr-Commit-Position: refs/branch-heads/3202@{#389}
Cr-Branched-From: fa6a5d87adff761bc16afc5498c3f5944c1daa68-refs/heads/master@{#499098}
[modify] https://crrev.com/46978193dcf59550857db0d32caf29beb3513605/chrome/browser/chromeos/fileapi/recent_arc_media_source.cc