This cl moves color and coverage off of drawstate.  In an effort to keep this CL manageable, I have left the compute invariant input / output in a bit of a strange state(fixing this will be complicated).

In addition, NVPR makes this very complicated, and I haven't quite figured out a good way to handle it, so for now color and coverage DO live on optstate, but I will figure out some way to refactor that in future CLs.

BUG=skia:

Review URL: https://codereview.chromium.org/783763002
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index c6dd2d7..c3c11b7 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -983,6 +983,7 @@
 
     void internalDrawPath(GrDrawTarget*,
                           GrDrawState*,
+                          GrColor,
                           bool useAA,
                           const SkPath&,
                           const GrStrokeInfo&);