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

1 files changed, 13 insertions, 0 deletions

diff --git a/src/gpu/GrBitmapTextContext.cpp b/src/gpu/GrBitmapTextContext.cpp
index e509e02437..48054f4eac 100755
--- a/src/gpu/GrBitmapTextContext.cpp
+++ b/src/gpu/GrBitmapTextContext.cpp
@@ -561,6 +561,7 @@ void GrBitmapTextContext::flush() {
                 // Color bitmap text
             case kARGB_GrMaskFormat:
                 SkASSERT(!drawState.hasColorVertexAttribute());
+                drawState.setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
                 drawState.setAlpha(fSkPaint.getAlpha());
                 break;
                 // LCD text
@@ -572,12 +573,24 @@ void GrBitmapTextContext::flush() {
                     SkDebugf("LCD Text will not draw correctly.\n");
                 }
                 SkASSERT(!drawState.hasColorVertexAttribute());
+                // We don't use the GrPaint's color in this case because it's been premultiplied by
+                // alpha. Instead we feed in a non-premultiplied color, and multiply its alpha by
+                // the mask texture color. The end result is that we get
+                //            mask*paintAlpha*paintColor + (1-mask*paintAlpha)*dstColor
+                int a = SkColorGetA(fSkPaint.getColor());
+                // paintAlpha
+                drawState.setColor(SkColorSetARGB(a, a, a, a));
+                // paintColor
+                drawState.setBlendConstant(skcolor_to_grcolor_nopremultiply(fSkPaint.getColor()));
+                drawState.setBlendFunc(kConstC_GrBlendCoeff, kISC_GrBlendCoeff);
                 break;
             }
                 // Grayscale/BW text
             case kA8_GrMaskFormat:
                 drawState.setHint(GrDrawState::kVertexColorsAreOpaque_Hint,
                                    0xFF == GrColorUnpackA(fPaint.getColor()));
+                // set back to normal in case we took LCD path previously.
+                drawState.setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
                 // We're using per-vertex color.
                 SkASSERT(drawState.hasColorVertexAttribute());
                 break;