Fixed xoom bug introduced in r5830

The xoom doesn't support shader derivatives or dual source blending. The lack of shader derivatives disables the AA convex path renderer resulting in more path's being drawn in software. r5830 short circuited some of the blend optimizations (by hiding the opaque paint color in the vertex colors) so when the resulting path masks were being drawn (in drawRect) the real blend had to be performed. Without dual source blending this is not possible for all blend modes.

This change turns off the vertex color-based batching for drawRects with texture thus re-enabling the blend optimizations. It leaves the performance improvement of r5830 unchanged on 'tablebench'.

[bsalomon, 2012-10-09 15:00:03]

https://codereview.appspot.com/6604053/diff/1/src/gpu/GrInOrderDrawBuffer.cpp
File src/gpu/GrInOrderDrawBuffer.cpp (right):

https://codereview.appspot.com/6604053/diff/1/src/gpu/GrInOrderDrawBuffer.cpp...
src/gpu/GrInOrderDrawBuffer.cpp:113: batchAcrossColors = false;
Should we also check whether dualSourceBlending() is enabled and whether the
xfer mode will require it?

DSB check is this->dualSourceBlendingSupport()

Somewhere we have a check for whether the xfer mode requires it, it could be
moved to a common header.

Also, am I right that it only matters if we have a coverage stage?  I think
we're OK with a regular texture.

[robertphillips, 2012-10-09 17:37:08]

https://codereview.appspot.com/6604053/diff/1/src/gpu/GrInOrderDrawBuffer.cpp
File src/gpu/GrInOrderDrawBuffer.cpp (right):

https://codereview.appspot.com/6604053/diff/1/src/gpu/GrInOrderDrawBuffer.cpp...
src/gpu/GrInOrderDrawBuffer.cpp:113: batchAcrossColors = false;
I added a check for DSB. I will take a TODO to add a check if DSB is required
for the blend mode.

[bsalomon, 2012-10-09 17:38:02]

On 2012/10/09 17:37:08, robertphillips wrote:
> https://codereview.appspot.com/6604053/diff/1/src/gpu/GrInOrderDrawBuffer.cpp
> File src/gpu/GrInOrderDrawBuffer.cpp (right):
> 
>
https://codereview.appspot.com/6604053/diff/1/src/gpu/GrInOrderDrawBuffer.cpp...
> src/gpu/GrInOrderDrawBuffer.cpp:113: batchAcrossColors = false;
> I added a check for DSB. I will take a TODO to add a check if DSB is required
> for the blend mode.

LGTM

[robertphillips, 2012-10-09 17:40:54]

committed as r5862