Revert of Add SkCodec, including PNG implementation.

Revert of Add SkCodec, including PNG implementation. (patchset #24 id:460001 of https://codereview.chromium.org/930283002/)

Reason for revert:
Breaking windows bots all over the place :(

Original issue's description:
> Add SkCodec, including PNG implementation.
> 
> DM:
> Add a flag to use SkCodec instead of SkImageDecoder.
> 
> SkCodec:
> Base class for codecs, allowing creation from an SkStream or an SkData.
> An SkCodec, on creation, knows properties of the data like its width and height. Further calls can be used to generate the image.
> TODO: Add scanline iterator
> 
> SkPngCodec:
> New decoder for png. Wraps libpng. The code has been repurposed from SkImageDecoder_libpng.
> TODO: Handle other destination colortypes
> TODO: Substitute the transpose color
> TODO: Allow silencing warnings
> TODO: Use RGB instead of filler?
> TODO: sRGB
> 
> SkSwizzler:
> Simplified version of SkScaledSampler. Unlike the sampler, this object does no sampling.
> TODO: Implement other swizzles.
> 
> BUG=skia:3257
> 
> Committed: https://skia.googlesource.com/skia/+/ca358852b4fed656d11107b2aaf28318a4518b49

TBR=reed@google.com,djsollen@google.com,msarett@google.com,mtklein@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:3257
Committed: https://skia.googlesource.com/skia/+/ee1a726aed980016a9371ffa4768e0844c360eb2

[scroggo, 2015-03-02 20:29:08]

Created Revert of Add SkCodec, including PNG implementation.

[commit-bot: I haz the power, 2015-03-02 20:31:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/972743003/1

[commit-bot: I haz the power, 2015-03-02 20:31:15]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/ee1a726aed980016a9371ffa4768e0844c360eb2