Use tristate in HW AA tracking, fix msaa disabled for non-smoothed lines bug

[bsalomon, 2012-05-21 15:50:44]

This is somewhat a tangent from the previous changes. The msaa/smooth line
tracking was already done outside fHWDrawState. This change uses the newly added
TriState rather than bools to take advantage of the unknown value. 

It also fixes the following bug. Line smoothing state in desktop GL is ignored
if MSAA is enabled. However, we were disabling MSAA for all lines, even when we
couldn't use the line smoothing.

http://codereview.appspot.com/6222051/diff/1/src/gpu/gl/GrGpuGL.cpp
File src/gpu/gl/GrGpuGL.cpp (left):

http://codereview.appspot.com/6222051/diff/1/src/gpu/gl/GrGpuGL.cpp#oldcode1944
src/gpu/gl/GrGpuGL.cpp:1944: GL_CALL(Disable(GR_GL_MULTISAMPLE));
The bug was here. We're disabling MSAA for all lines, smooth or not.

[robertphillips, 2012-05-21 16:33:24]

LGTM

http://codereview.appspot.com/6222051/diff/1/src/gpu/gl/GrGpuGL.cpp
File src/gpu/gl/GrGpuGL.cpp (right):

http://codereview.appspot.com/6222051/diff/1/src/gpu/gl/GrGpuGL.cpp#newcode468
src/gpu/gl/GrGpuGL.cpp:468: // should we also disable polygon smoothing?
I think we should

[TomH, 2012-05-21 16:35:21]

LGTM

http://codereview.appspot.com/6222051/diff/1/src/gpu/gl/GrGpuGL.cpp
File src/gpu/gl/GrGpuGL.cpp (right):

http://codereview.appspot.com/6222051/diff/1/src/gpu/gl/GrGpuGL.cpp#newcode468
src/gpu/gl/GrGpuGL.cpp:468: // should we also disable polygon smoothing?
On 2012/05/21 16:33:24, robertphillips wrote:
> I think we should
SGTM

[bsalomon, 2012-05-21 17:12:37]

Committed as r4015. I'll prepare a separate change that does the polygon smooth
(and other state) disable.