Minimize use of SkDraw's matrix in SkGpuDevice.

Minimize use of SkDraw's matrix in SkGpuDevice.

R=robertphillips@google.com
Committed: https://code.google.com/p/skia/source/detail?r=5906

[bsalomon, 2012-10-10 20:54:18]

The idea is to make the model that the SkDraw is used to update GrContext in
prepareDraw() and never looked at again. From then on we rely the GrContext's
matrix. This change changes reads of SkDraw's matrix to GrContext's matrix. It
also removes some instances where SkDraw or SkDraw::fMatrix is passed to
functions that already took GrContext and the SkDraw's matrix is therefore
redundant.

There is one exception to the never look at the SkDraw again rule:

Sometimes we create a new SkDraw with a modified matrix in order to do a
recursive draw call on SkGpuDevice.

https://codereview.appspot.com/6604068/diff/1/src/gpu/SkGpuDevice.cpp
File src/gpu/SkGpuDevice.cpp (right):

https://codereview.appspot.com/6604068/diff/1/src/gpu/SkGpuDevice.cpp#newcode949
src/gpu/SkGpuDevice.cpp:949: if
(!grp->preConcatSamplerMatricesWithInverse(context->getMatrix())) {
This mess will be cleaned up with a later CL that improves AutoMatrix. It will
take an optional paint param and the paint's stages will be updated wrt to the
view-matrix change

[robertphillips, 2012-10-10 22:52:33]

LGTM + 1 possible code rearrangement

https://codereview.appspot.com/6604068/diff/1/src/gpu/SkGpuDevice.cpp
File src/gpu/SkGpuDevice.cpp (right):

https://codereview.appspot.com/6604068/diff/1/src/gpu/SkGpuDevice.cpp#newcode...
src/gpu/SkGpuDevice.cpp:1267: 
I think it might be better to have this (in some form) in SkClipStack. With a
comment.

[bsalomon, 2012-10-11 13:26:23]

https://codereview.appspot.com/6604068/diff/1/src/gpu/SkGpuDevice.cpp
File src/gpu/SkGpuDevice.cpp (right):

https://codereview.appspot.com/6604068/diff/1/src/gpu/SkGpuDevice.cpp#newcode...
src/gpu/SkGpuDevice.cpp:1267: 
On 2012/10/10 22:52:34, robertphillips wrote:
> I think it might be better to have this (in some form) in SkClipStack. With a
> comment.

Good suggestion! Done in the latest patchset.

[robertphillips, 2012-10-11 13:37:21]

LGTM