Use SkShader's localMat for SkLocalMatrixShader.

Use SkShader's localMat for SkLocalMatrixShader.

Instead of setting SkShader::fLocalMatrix to Identity and storing
a separate SkMatrix inside SkLocalMatrixShader, reuse
SkShader::fLocalMatrix.

Committed: https://skia.googlesource.com/skia/+/c870d494dd0dc88f3f4155a0d6257a1be8280880

[reed1, 2014-07-10 21:07:11]

modulo chrome flattening proxies (not sure that they do) lgtm

I certainly like the simplification.

[scroggo, 2014-07-10 21:25:25]

On 2014/07/10 21:07:11, reed1 wrote:
> modulo chrome flattening proxies (not sure that they do) lgtm
> 
> I certainly like the simplification.

It appears that they could, if they are using SkRectShaderImageFilter.cpp.

Uploaded a new patch with the ability to read old pictures.

[scroggo, 2014-07-10 22:40:59]

On 2014/07/10 21:25:25, scroggo wrote:
> On 2014/07/10 21:07:11, reed1 wrote:
> > modulo chrome flattening proxies (not sure that they do) lgtm
> > 
> > I certainly like the simplification.
> 
> It appears that they could, if they are using SkRectShaderImageFilter.cpp.
> 
> Uploaded a new patch with the ability to read old pictures.

Latest patch just adds a FIXME, documenting the case we discussed that does
not work quite correctly:

  SkShader* s = <factory>(someLocalMatrix);
  SkShader* sPrime = SkShader::CreateLocalMatrixShader(s, someOtherLocalMatrix);
  SkMatrix m = sPrime->getLocalMatrix();

m does not take <someLocalMatrix> into account.

[scroggo, 2014-07-11 14:22:05]

On 2014/07/10 22:40:59, scroggo wrote:
> On 2014/07/10 21:25:25, scroggo wrote:
> > On 2014/07/10 21:07:11, reed1 wrote:
> > > modulo chrome flattening proxies (not sure that they do) lgtm
> > > 
> > > I certainly like the simplification.
> > 
> > It appears that they could, if they are using SkRectShaderImageFilter.cpp.
> > 
> > Uploaded a new patch with the ability to read old pictures.
> 
> Latest patch just adds a FIXME, documenting the case we discussed that does
> not work quite correctly:
> 
>   SkShader* s = <factory>(someLocalMatrix);
>   SkShader* sPrime = SkShader::CreateLocalMatrixShader(s,
someOtherLocalMatrix);
>   SkMatrix m = sPrime->getLocalMatrix();
> 
> m does not take <someLocalMatrix> into account.

And, because I'm picky, patch set 4 attempts to make the comment a little more
clear.

[scroggo, 2014-07-11 17:17:37]

The CQ bit was checked by scroggo@google.com

[commit-bot: I haz the power, 2014-07-11 17:18:40]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/scroggo@google.com/386693003/60001

[commit-bot: I haz the power, 2014-07-11 17:42:15]

Change committed as c870d494dd0dc88f3f4155a0d6257a1be8280880