Axis aligned shader-based rect drawing

This adds a specialized rect effect for Axis Aligned rects. It is faster then the general rect effect but still not always faster then the geometric approach (geometry on left - axis aligned on right):

Win7

drawpointsdash_1_1_aa GPU c         65.91      70.51      -4.60    -7.0%
drawpointsdash_5_5_aa GPU c         21.76      23.24      -1.48    -6.8%
                          aarects GPU c         36.66      38.92      -2.26    -6.2%
drawpointsdash_3_1_aa GPU c         30.89      32.21      -1.32    -4.3%
                   tablebench GPU c         24.96      25.82      -0.86    -3.4%

MacPro

drawpointsdash_3_1_aa GPU c         37.40      40.33      -2.93    -7.8%
drawpointsdash_1_1_aa GPU c         85.36      91.90      -6.54    -7.7%
              aarects GPU c         47.60      51.26      -3.66    -7.7%
drawpointsdash_5_5_aa GPU c         26.74      27.92      -1.18    -4.4%
           tablebench GPU c         35.05      35.14      -0.09    -0.3%

Nexus 7

drawpointsdash_5_5_aa GPU c        323.14     210.74    +112.40   +34.8% 
           tablebench GPU c        337.85     173.46    +164.39   +48.7% 
              aarects GPU c       2494.74    1065.79   +1428.95   +57.3% 
drawpointsdash_3_1_aa GPU c        822.38     310.22    +512.16   +62.3% 
drawpointsdash_1_1_aa GPU c       4676.73    1060.48   +3616.25   +77.3% 

I would like to land this disabled as a checkpoint.

[bsalomon, 2013-04-29 19:44:50]

https://codereview.chromium.org/14314004/diff/2002/include/gpu/GrAARectRender...
File include/gpu/GrAARectRenderer.h (right):

https://codereview.chromium.org/14314004/diff/2002/include/gpu/GrAARectRender...
include/gpu/GrAARectRenderer.h:54: void shaderFillAAAARect(GrGpu* gpu,
umm... AlignedAARect?

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrAARectRenderer.cpp
File src/gpu/GrAARectRenderer.cpp (right):

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrAARectRenderer.c...
src/gpu/GrAARectRenderer.cpp:17: class GrGLAARectEffect;
AlignedRectEffect? It seems like we've reserved AA for anti-aliased and its
confusing to use it for axis-aligned.

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrContext.cpp
File src/gpu/GrContext.cpp (right):

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrContext.cpp#newc...
src/gpu/GrContext.cpp:811: if (combinedMatrix.rectStaysRect()) {
Seems cleaner to me make axis-aligned vs not an implementation detail of the
renderer class rather than part of its API.

[jvanverth1, 2013-04-29 19:46:28]

https://codereview.chromium.org/14314004/diff/2002/include/gpu/GrAARectRender...
File include/gpu/GrAARectRenderer.h (right):

https://codereview.chromium.org/14314004/diff/2002/include/gpu/GrAARectRender...
include/gpu/GrAARectRenderer.h:54: void shaderFillAAAARect(GrGpu* gpu,
Yes, at first glance it's unclear what this method does, as amusing as it might
be to think of a surprised rect.

[jvanverth1, 2013-04-29 20:02:42]

One other comment:

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrAARectRenderer.cpp
File src/gpu/GrAARectRenderer.cpp (right):

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrAARectRenderer.c...
src/gpu/GrAARectRenderer.cpp:467: 
Is this different from 0.5*devRect.width() + 0.5? Seems to me it shouldn't be.

[robertphillips, 2013-05-02 13:56:39]

PTAL

https://codereview.chromium.org/14314004/diff/2002/include/gpu/GrAARectRender...
File include/gpu/GrAARectRenderer.h (right):

https://codereview.chromium.org/14314004/diff/2002/include/gpu/GrAARectRender...
include/gpu/GrAARectRenderer.h:54: void shaderFillAAAARect(GrGpu* gpu,
Done (shaderFillAlignedAARect).

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrAARectRenderer.cpp
File src/gpu/GrAARectRenderer.cpp (right):

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrAARectRenderer.c...
src/gpu/GrAARectRenderer.cpp:17: class GrGLAARectEffect;
On 2013/04/29 19:44:50, bsalomon wrote:
> AlignedRectEffect? It seems like we've reserved AA for anti-aliased and its
> confusing to use it for axis-aligned.

Done.

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrAARectRenderer.c...
src/gpu/GrAARectRenderer.cpp:467: 
newWidth and newHeight are relative to 'dir' so they need to be transformed x
and y vectors. This distinction is only relevant in the rotated case.

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrContext.cpp
File src/gpu/GrContext.cpp (right):

https://codereview.chromium.org/14314004/diff/2002/src/gpu/GrContext.cpp#newc...
src/gpu/GrContext.cpp:811: if (combinedMatrix.rectStaysRect()) {
Done. Note that this change will make more sense if/when the rotated geometric
AA rects CL lands.

[bsalomon, 2013-05-02 14:02:16]

lgtm

[robertphillips, 2013-05-02 15:37:39]

committed as r8960