Revert of factories should return baseclass, allowing the impl to specialize

Revert of factories should return baseclass, allowing the impl to specialize (patchset #4 id:60001 of https://codereview.chromium.org/1390523005/ )

Reason for revert:
Breaks Chrome with this link error: ../../third_party/skia/include/effects/SkMorphologyImageFilter.h:75: error: undefined reference to 'SkMorphologyImageFilter::SkMorphologyImageFilter(int, int, SkImageFilter*, SkImageFilter::CropRect const*)'
../../third_party/skia/include/effects/SkMorphologyImageFilter.h:104: error: undefined reference to 'SkMorphologyImageFilter::SkMorphologyImageFilter(int, int, SkImageFilter*, SkImageFilter::CropRect const*)'

Presumably due to code in third_party/WebKit/Source/platform/graphics/filters/FEMorphology.cpp that contains:
#include "SkMorphologyImageFilter.h"

...

    if (m_type == FEMORPHOLOGY_OPERATOR_DILATE)
        return adoptRef(SkDilateImageFilter::Create(radiusX, radiusY, input.get(), &rect));
    return adoptRef(SkErodeImageFilter::Create(radiusX, radiusY, input.get(), &rect));


Original issue's description:
> factories should return baseclass, allowing the impl to specialize
> 
> waiting on https://codereview.chromium.org/1386163002/# to land
> 
> BUG=skia:4424
> 
> Committed: https://skia.googlesource.com/skia/+/80a6dcaa1b757826ed7414f64b035d512d9ccbf8

TBR=senorblanco@google.com,robertphillips@google.com,reed@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4424
Committed: https://skia.googlesource.com/skia/+/95376a0dde3cdf414eb97a20cef3af19ed7e0151

[Stephen Chennney, 2015-10-06 19:54:59]

Created Revert of factories should return baseclass, allowing the impl to
specialize

[commit-bot: I haz the power, 2015-10-06 19:55:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1389063002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1389063002/1

[commit-bot: I haz the power, 2015-10-06 19:55:19]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-10-07 01:55 UTC

[Stephen White, 2015-10-06 19:59:11]

On 2015/10/06 19:55:19, commit-bot: I haz the power wrote:
> Note for Reviewers:
> The CQ is waiting for an approval.
> If you believe that the CL is not ready yet, or if you would like to L-G-T-M
> with comments then please uncheck the CQ checkbox.
> 
> Waiting for LGTM from valid reviewer(s) till 2015-10-07 01:55 UTC

LGTM (although I think you should land roll-blocking reverts TBR)

[Stephen White, 2015-10-06 19:59:39]

Oh wait, you did. Not sure what the CQ is talking about here, then.

[commit-bot: I haz the power, 2015-10-06 20:00:00]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/95376a0dde3cdf414eb97a20cef3af19ed7e0151

[Stephen Chennney, 2015-10-06 20:07:34]

The problem was the removal of SK_API on SkMorphologyImageFilter