Remove attribute matrix support

[bsalomon, 2012-05-11 20:25:04]

Remove support for uploading view/texture matrices as vertex data. This was
originally added because it proved faster on the iPad 1 in some scenarios. It
hasn't been used or tested in over a year. Perhaps it may still make sense on
some hw(?). However, removing it for now seems to make two things easier:

1) swallowing management of the texture matrix by the custom effect code

2) Removing GrGpuGL's GrDrawState fHWDrawState as a way of keeping track of
elements of the GPU state. This has become a bad mismatch over time and I'm
working on removing it. It's copies of sampler matrices and view matrix are used
as the cached copy for the attrib case only.

[TomH, 2012-05-11 20:42:04]

LGTM

[bsalomon, 2012-05-21 22:17:35]

Closed with r3917.