Make GrGLSLProgramBuilder base class for ProgramBuilder

Make GrGLSLProgramBuilder base class for GrGLProgramBuilder.

This CL still keeps the weird diamond shape we have for all our ProgramBuilders.
However, the GrGLSL base class will allow us to pull multiple other parts
of our program setup away from GL which will eventually allow us to break up
the diamond. 

As part of this all ShaderBuilder subclass have been made gl independent,
however I will move them to GLSL files/class names in a follow on CL.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/8dcdedc4a087ea46ce1e2458d335d60918e56310

[egdaniel, 2015-11-10 20:27:24]

Description was changed from

==========
Make GrGLSLProgramBuilder base class for ProgramBuilder

As part of this all ShaderBuilder subclass have been made gl independent,
however I will move them to GLSL files/class names in a follow on CL.

BUG=skia:
==========

to

==========
Make GrGLSLProgramBuilder base class for GrGLProgramBuilder.
This CL still keeps the weird diamond shape we have for all our ProgramBuilders.
However, the GrGLSL base class will allow us to pull multiple other parts of our
program setup away from GL which will eventually allow us to break up the
diamond. 

As part of this all ShaderBuilder subclass have been made gl independent,
however I will move them to GLSL files/class names in a follow on CL.

BUG=skia:
==========

[egdaniel, 2015-11-10 20:47:55]

Description was changed from

==========
Make GrGLSLProgramBuilder base class for GrGLProgramBuilder.
This CL still keeps the weird diamond shape we have for all our ProgramBuilders.
However, the GrGLSL base class will allow us to pull multiple other parts of our
program setup away from GL which will eventually allow us to break up the
diamond. 

As part of this all ShaderBuilder subclass have been made gl independent,
however I will move them to GLSL files/class names in a follow on CL.

BUG=skia:
==========

to

==========
Make GrGLSLProgramBuilder base class for GrGLProgramBuilder.

This CL still keeps the weird diamond shape we have for all our ProgramBuilders.
However, the GrGLSL base class will allow us to pull multiple other parts
of our program setup away from GL which will eventually allow us to break up
the diamond. 

As part of this all ShaderBuilder subclass have been made gl independent,
however I will move them to GLSL files/class names in a follow on CL.

BUG=skia:
==========

[egdaniel, 2015-11-10 20:48:32]

egdaniel@google.com changed reviewers:
+ bsalomon@google.com, ethannicholas@google.com

[bsalomon, 2015-11-10 21:23:03]

lgtm

https://codereview.chromium.org/1416423003/diff/1/src/gpu/glsl/GrGLSLProgramB...
File src/gpu/glsl/GrGLSLProgramBuilder.h (right):

https://codereview.chromium.org/1416423003/diff/1/src/gpu/glsl/GrGLSLProgramB...
src/gpu/glsl/GrGLSLProgramBuilder.h:37: supported at this time. The actual
uniform name will be mangled. If outName is not nullptr then
wrap (looks like this got messed up by NULL->nullptr search and replace, ok to
change back to simply "null")

[egdaniel, 2015-11-11 14:15:44]

The CQ bit was checked by egdaniel@google.com

[egdaniel, 2015-11-11 14:15:45]

The patchset sent to the CQ was uploaded after l-g-t-m from bsalomon@google.com
Link to the patchset: https://codereview.chromium.org/1416423003/#ps20001
(title: "nit")

[commit-bot: I haz the power, 2015-11-11 14:15:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1416423003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1416423003/20001

[commit-bot: I haz the power, 2015-11-11 14:27:23]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/8dcdedc4a087ea46ce1e2458d335d60918e56310