Enable vp09 codec string in WebM by default

Enable vp09 codec string in WebM by default

Removes need for command line switch --enable-new-vp9-codec-string

BUG=727902
Review-Url: https://codereview.chromium.org/2917463002
Cr-Original-Commit-Position: refs/heads/master@{#477749}
Review-Url: https://codereview.chromium.org/2926393002 .
Cr-Commit-Position: refs/branch-heads/3112@{#267}
Cr-Branched-From: b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed: https://chromium.googlesource.com/chromium/src/+/384201c1babf1efffbf2db9760df832f6fd77c18

[chcunningham, 2017-06-08 20:52:59]

Description was changed from

==========
Enable vp09 codec string in WebM by default

Removes need for command line switch --enable-new-vp9-codec-string

BUG=727902

Review-Url: https://codereview.chromium.org/2917463002
Cr-Commit-Position: refs/heads/master@{#477749}
(cherry picked from commit 6d43fc8beaa41811acc6c77a56ab2174ca283788)
==========

to

==========
Enable vp09 codec string in WebM by default

Removes need for command line switch --enable-new-vp9-codec-string

BUG=727902

Review-Url: https://codereview.chromium.org/2917463002
Cr-Original-Commit-Position: refs/heads/master@{#477749}
Review-Url: https://codereview.chromium.org/2926393002 .
Cr-Commit-Position: refs/branch-heads/3112@{#267}
Cr-Branched-From:
b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed:
https://chromium.googlesource.com/chromium/src/+/384201c1babf1efffbf2db9760df...
==========

[chcunningham, 2017-06-08 20:53:00]

Committed patchset #1 (id:1) manually as
384201c1babf1efffbf2db9760df832f6fd77c18.