Revert of Refactor to put SkXfermode_opts inside SK_OPTS_NS.

Revert of Refactor to put SkXfermode_opts inside SK_OPTS_NS. (patchset #1 id:1 of https://codereview.chromium.org/1286093004/ )

Reason for revert:
Maybe causing test / gold problems?

Original issue's description:
> Refactor to put SkXfermode_opts inside SK_OPTS_NS.
> 
> Without this refactor I was getting warnings previously about having code
> inside namespace SK_OPTS_NS (e.g. namespace sse2, namespace neon) referring to
> code inside an anonymous namespace (Sk4px, SkPMFloat, Sk4f, etc) [1].
> 
> That low-level code was in an anonymous namespace to allow multiple independent
> copies of its methods to be instantiated without the linker getting confused /
> offended about violating the One Definition Rule.  This was only happening in
> Debug mode where the methods were not being inlined.
> 
> To fix this all, I've force-inlined the methods of the low-level code and
> removed the anonymous namespace.
> 
> BUG=skia:4117
> 
> 
> [1] Here is what those errors looked like:
> 
> In file included from ../../../../src/core/SkOpts.cpp:18:0:
> ../../../../src/opts/SkXfermode_opts.h:193:7: error: 'portable::Sk4pxXfermode' has a field 'portable::Sk4pxXfermode::fProc4' whose type uses the anonymous namespace [-Werror]
>  class Sk4pxXfermode : public SkProcCoeffXfermode {
>        ^
> ../../../../src/opts/SkXfermode_opts.h:193:7: error: 'portable::Sk4pxXfermode' has a field 'portable::Sk4pxXfermode::fAAProc4' whose type uses the anonymous namespace [-Werror]
> ../../../../src/opts/SkXfermode_opts.h:235:7: error: 'portable::SkPMFloatXfermode' has a field 'portable::SkPMFloatXfermode::fProcF' whose type uses the anonymous namespace [-Werror]
>  class SkPMFloatXfermode : public SkProcCoeffXfermode {
>        ^
> cc1plus: all warnings being treated as errors
> 
> Committed: https://skia.googlesource.com/skia/+/b07bee3121680b53b98b780ac08d14d374dd4c6f

TBR=djsollen@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4117
Committed: https://skia.googlesource.com/skia/+/082e329887a8f1efe4e1020f0a0a6ea09961712d

[mtklein, 2015-08-12 18:56:25]

Created Revert of Refactor to put SkXfermode_opts inside SK_OPTS_NS.

[commit-bot: I haz the power, 2015-08-12 18:56:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1284333002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1284333002/1

[commit-bot: I haz the power, 2015-08-12 18:56:49]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/082e329887a8f1efe4e1020f0a0a6ea09961712d