Thanks for investigating this :) We should target M57 and try M56 given that it creates weird inconsistencies for WebView.

+torne@ FYI

Yeah, seems fine to enable this.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/faaa2fd0a05f1622d9a8806da118d4f3b602e707

commit faaa2fd0a05f1622d9a8806da118d4f3b602e707
Author: zqzhang <zqzhang@chromium.org>
Date: Mon Feb 06 22:48:42 2017

[Blink>Media] Allow autoplay muted on Android by default

There was a mistake causing autoplay muted is shipped on Android
but it will be disabled if the chromium embedder doesn't specify
content setting for "AllowAutoplay" preference. This CL makes the
AllowAutoplay preference true by default so that it is allowed by
embedders (including AndroidWebView) unless they explicitly
disable it.

Intent to ship:
https://groups.google.com/a/chromium.org/d/msg/blink-dev/Q1cnzNI2GpI/AL_eyUNABgAJ

BUG= 689018 

Review-Url: https://codereview.chromium.org/2677173002
Cr-Commit-Position: refs/heads/master@{#448423}

[modify] https://crrev.com/faaa2fd0a05f1622d9a8806da118d4f3b602e707/components/test_runner/mock_content_settings_client.cc
[modify] https://crrev.com/faaa2fd0a05f1622d9a8806da118d4f3b602e707/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp

Let's merge it into M57 and possibly M56.

Your change meets the bar and is auto-approved for M57. Please go ahead and merge the CL to branch 2987 manually. Please contact milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), ketakid@(cros), govind@(desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8751b1bef69241c66929f923ea65dbe165dd6878

commit 8751b1bef69241c66929f923ea65dbe165dd6878
Author: Zhiqiang Zhang <zqzhang@google.com>
Date: Tue Feb 07 10:46:05 2017

[Blink>Media] Allow autoplay muted on Android by default

There was a mistake causing autoplay muted is shipped on Android
but it will be disabled if the chromium embedder doesn't specify
content setting for "AllowAutoplay" preference. This CL makes the
AllowAutoplay preference true by default so that it is allowed by
embedders (including AndroidWebView) unless they explicitly
disable it.

Intent to ship:
https://groups.google.com/a/chromium.org/d/msg/blink-dev/Q1cnzNI2GpI/AL_eyUNABgAJ

BUG= 689018 

Review-Url: https://codereview.chromium.org/2677173002
Cr-Commit-Position: refs/heads/master@{#448423}
(cherry picked from commit faaa2fd0a05f1622d9a8806da118d4f3b602e707)

Review-Url: https://codereview.chromium.org/2681673002 .
Cr-Commit-Position: refs/branch-heads/2987@{#358}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}

[modify] https://crrev.com/8751b1bef69241c66929f923ea65dbe165dd6878/components/test_runner/mock_content_settings_client.cc
[modify] https://crrev.com/8751b1bef69241c66929f923ea65dbe165dd6878/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp

Verified on LG V20 NRD90M MonoChrome version 58.0.3007.0.

Removing merge request to M56 as it has already in stable (too late for merging).