Remove a SkImageDecoder reference from SkPicture.h

Remove a SkImageDecoder reference from SkPicture.h

Remove SkImageDecoder::DecodeMemory reference from the default proc parameter of
SkPicture::CreateFromStream. Instead add an overload of CreateFromStream without
the proc parameter. Make compilations with image library call the old function
with the correct proc parameter. Make compilations without image library call
the old function with NULL parameter.

This is part of the work making it possible to compile core skia library without
references to image decoders or encoders, e.g without the images library. This
is needed in order to compile the images library to the standalone apps linking
to the images-less Skia library.

BUG=skia:2992

[Kimmo Kinnunen, 2014-10-20 12:49:26]

kkinnunen@nvidia.com changed reviewers:
+ reed@google.com, scroggo@google.com

[Kimmo Kinnunen, 2014-10-20 12:49:27]

Depends on:
https://codereview.chromium.org/665913002/

[scroggo, 2014-10-20 17:55:23]

On 2014/10/20 12:49:27, Kimmo Kinnunen wrote:
> Depends on:
> https://codereview.chromium.org/665913002/

Currently, you can call SkPicture::CreateFromStream without building the images
sublibrary by building SkImageDecoder_empty.cpp. How is this approach
better/meaningfully different?

[Kimmo Kinnunen, 2014-10-20 18:27:30]

On 2014/10/20 17:55:23, scroggo wrote:
> On 2014/10/20 12:49:27, Kimmo Kinnunen wrote:
> > Depends on:
> > https://codereview.chromium.org/665913002/
> 
> Currently, you can call SkPicture::CreateFromStream without building the
images
> sublibrary by building SkImageDecoder_empty.cpp. How is this approach
> better/meaningfully different?

SkImageDecoder_empty.cpp is an implementation of SkImageDecoder.
Can't have Skia have one implementation and the app have another implementation,
symbols clash.

[scroggo, 2016-02-12 19:01:35]

On 2014/10/20 18:27:30, Kimmo Kinnunen wrote:
> On 2014/10/20 17:55:23, scroggo wrote:
> > On 2014/10/20 12:49:27, Kimmo Kinnunen wrote:
> > > Depends on:
> > > https://codereview.chromium.org/665913002/
> > 
> > Currently, you can call SkPicture::CreateFromStream without building the
> images
> > sublibrary by building SkImageDecoder_empty.cpp. How is this approach
> > better/meaningfully different?
> 
> SkImageDecoder_empty.cpp is an implementation of SkImageDecoder.
> Can't have Skia have one implementation and the app have another
implementation,
> symbols clash.

Alternate solution in crrev.com/1671193002