Remove staging for SkImageDecoder::Peeker

Remove staging for SkImageDecoder::Peeker

Will no longer be needed once ag/817367 lands - Android will be
inheriting directly from SkPngChunkReader, so no need for the
intermediate.

BUG=skia:4574
Committed: https://skia.googlesource.com/skia/+/f01610effccd3fba2be5cec5dc10fbf9af5744a0

[scroggo, 2015-12-03 17:27:55]

scroggo@google.com changed reviewers:
+ msarett@google.com

[msarett, 2015-12-03 18:16:32]

lgtm

[reed1, 2015-12-03 19:40:07]

reed@google.com changed reviewers:
+ reed@google.com

[reed1, 2015-12-03 19:40:08]

api lgtm

[scroggo, 2015-12-08 22:03:15]

The CQ bit was checked by scroggo@google.com

[commit-bot: I haz the power, 2015-12-08 22:03:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1470913004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1470913004/1

[commit-bot: I haz the power, 2015-12-09 02:48:42]

Description was changed from

==========
Remove staging for SkImageDecoder::Peeker

Will no longer be needed once ag/817367 lands - Android will be
inheriting directly from SkPngChunkReader, so no need for the
intermediate.

BUG=skia:4574
==========

to

==========
Remove staging for SkImageDecoder::Peeker

Will no longer be needed once ag/817367 lands - Android will be
inheriting directly from SkPngChunkReader, so no need for the
intermediate.

BUG=skia:4574

Committed:
https://skia.googlesource.com/skia/+/f01610effccd3fba2be5cec5dc10fbf9af5744a0
==========

[commit-bot: I haz the power, 2015-12-09 02:48:42]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/f01610effccd3fba2be5cec5dc10fbf9af5744a0