Revert[8] "replace SkXfermode obj with SkBlendMode enum in paints"

src/gpu/GrDrawContext.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBatchTest.h"
 #include "GrColor.h"
 #include "GrDrawContext.h"
@@ skipping 223 matching lines @@
         // target before the target is read.
         SkRect clearRect = SkRect::MakeIWH(this->width(), this->height());
         if (isFull) {
             this->discard();
         } else if (!clearRect.intersect(SkRect::Make(clip.scissorRect()))) {
             return;
         }
 
         GrPaint paint;
         paint.setColor4f(GrColor4f::FromGrColor(color));
-        paint.setXPFactory(GrPorterDuffXPFactory::Make(SkXfermode::kSrc_Mode));
+        paint.setXPFactory(GrPorterDuffXPFactory::Make(SkXfermode::Mode::kSrc_Mode));
 
         this->drawRect(clip, paint, SkMatrix::I(), clearRect);
     } else if (isFull) {
         this->getDrawTarget()->fullClear(this->accessRenderTarget(), color);
     } else {
         sk_sp<GrBatch> batch(GrClearBatch::Make(clip, color, this->accessRenderTarget()));
         if (!batch) {
             return;
         }
         this->getDrawTarget()->addBatch(std::move(batch));
@@ skipping 1171 matching lines @@
 
 void GrDrawContext::drawBatch(const GrPipelineBuilder& pipelineBuilder, const GrClip& clip,
                               GrDrawBatch* batch) {
     ASSERT_SINGLE_OWNER
     RETURN_IF_ABANDONED
     SkDEBUGCODE(this->validate();)
     GR_AUDIT_TRAIL_AUTO_FRAME(fAuditTrail, "GrDrawContext::drawBatch");
 
     this->getDrawTarget()->drawBatch(pipelineBuilder, this, clip, batch);
 }