Revert of Make all blending up to GrOptDrawState be handled by the xp/xp factory. (patchset #7 id:140001 of https://codereview.chromium.org/759713002/)

Reason for revert:
break many gm's

Original issue's description:
> Make all blending up to GrOptDrawState be handled by the xp/xp factory.
>
> In this cl the blending information is extracted for the xp and stored in the ODS
> which is then used as it currently is. In the follow up cl, an XP backend will be added
> and at that point all blending work will take place inside XP's.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/7c66342a399b529634bed0fabfaa562db2c0dbd4

TBR=bsalomon@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/766653008
diff --git a/gm/texdata.cpp b/gm/texdata.cpp
index 56dfd24..efe8c4d 100644
--- a/gm/texdata.cpp
+++ b/gm/texdata.cpp
@@ -12,9 +12,8 @@
 
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
-#include "SkColorPriv.h"
-#include "effects/GrPorterDuffXferProcessor.h"
 #include "effects/GrSimpleTextureEffect.h"
+#include "SkColorPriv.h"
 
 namespace skiagm {
 
@@ -99,8 +98,7 @@
                 ctx->setRenderTarget(target);
 
                 GrPaint paint;
-                paint.setPorterDuffXPFactory(SkXfermode::kSrcOver_Mode);
-
+                paint.setBlendFunc(kOne_GrBlendCoeff, kISA_GrBlendCoeff);
                 SkMatrix vm;
                 if (i) {
                     vm.setRotate(90 * SK_Scalar1,