Delete unused method FilesystemInterface::IsAbsent.

Delete unused method FilesystemInterface::IsAbsent.

BUG=webrtc:6424
Review-Url: https://codereview.webrtc.org/3012583002
Cr-Commit-Position: refs/heads/master@{#19620}
Committed: https://chromium.googlesource.com/external/webrtc/+/125e95eaf6c04faec20f85b7d7949f961fc12aea

[nisse-webrtc, 2017-08-30 13:37:02]

nisse@webrtc.org changed reviewers:
+ deadbeef@webrtc.org

[nisse-webrtc, 2017-08-30 13:37:03]

PTAL.

[Taylor Brandstetter, 2017-08-30 22:50:32]

lgtm

[nisse-webrtc, 2017-08-31 06:42:24]

The CQ bit was checked by nisse@webrtc.org

[commit-bot: I haz the power, 2017-08-31 06:42:37]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-08-31 07:22:07]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1504161744666580, "parent_rev":
"46f9b6cbb835f9634ddd2ad8a25c1645bea12521", "commit_rev":
"125e95eaf6c04faec20f85b7d7949f961fc12aea"}

[commit-bot: I haz the power, 2017-08-31 07:22:11]

Description was changed from

==========
Delete unused method FilesystemInterface::IsAbsent.

BUG=webrtc:6424
==========

to

==========
Delete unused method FilesystemInterface::IsAbsent.

BUG=webrtc:6424

Review-Url: https://codereview.webrtc.org/3012583002
Cr-Commit-Position: refs/heads/master@{#19620}
Committed:
https://chromium.googlesource.com/external/webrtc/+/125e95eaf6c04faec20f85b7d...
==========

[commit-bot: I haz the power, 2017-08-31 07:22:13]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/125e95eaf6c04faec20f85b7d...