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

src/core/SkCanvas.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
 #include "SkCanvasPriv.h"
@@ skipping 466 matching lines @@
              *      Remove the imagefilter and the xfermode from the paint that we (AutoDrawLooper)
              *      return (fPaint). We then draw the primitive (using srcover) into a cleared
              *      buffer/surface.
              *  3. Restore the layer created in #1
              *      The imagefilter is passed the buffer/surface from the layer (now filled with the
              *      src pixels of the primitive). It returns a new "filtered" buffer, which we
              *      draw onto the previous layer using the xfermode from the original paint.
              */
             SkPaint tmp;
             tmp.setImageFilter(fPaint->getImageFilter());
-            tmp.setXfermode(sk_ref_sp(fPaint->getXfermode()));
+            tmp.setBlendMode(fPaint->getBlendMode());
             SkRect storage;
             if (rawBounds) {
                 // Make rawBounds include all paint outsets except for those due to image filters.
                 rawBounds = &apply_paint_to_bounds_sans_imagefilter(*fPaint, *rawBounds, &storage);
             }
             (void)canvas->internalSaveLayer(SkCanvas::SaveLayerRec(rawBounds, &tmp),
                                             SkCanvas::kFullLayer_SaveLayerStrategy);
             fTempLayerForImageFilter = true;
             // we remove the imagefilter/xfermode inside doNext()
         }
@@ skipping 53 matching lines @@
 bool AutoDrawLooper::doNext(SkDrawFilter::Type drawType) {
     fPaint = nullptr;
     SkASSERT(!fIsSimple);
     SkASSERT(fLooperContext || fFilter || fTempLayerForImageFilter);
 
     SkPaint* paint = fLazyPaintPerLooper.set(fLazyPaintInit.isValid() ?
                                              *fLazyPaintInit.get() : fOrigPaint);
 
     if (fTempLayerForImageFilter) {
         paint->setImageFilter(nullptr);
-        paint->setXfermode(nullptr);
+        paint->setBlendMode(SkBlendMode::kSrcOver);
     }
 
     if (fLooperContext && !fLooperContext->next(fCanvas, paint)) {
         fDone = true;
         return false;
     }
     if (fFilter) {
         if (!fFilter->filter(paint, drawType)) {
             fDone = true;
             return false;
@@ skipping 2055 matching lines @@
 }
 
 void SkCanvas::DrawTextDecorations(const SkDraw& draw, const SkPaint& paint,
                                    const char text[], size_t byteLength,
                                    SkScalar x, SkScalar y) {
     SkASSERT(byteLength == 0 || text != nullptr);
 
     // nothing to draw
     if (text == nullptr || byteLength == 0 ||
         draw.fRC->isEmpty() ||
-        (paint.getAlpha() == 0 && paint.getXfermode() == nullptr)) {
+        (paint.getAlpha() == 0 && paint.isSrcOver())) {
         return;
     }
 
     SkScalar    width = 0;
     SkPoint     start;
 
     start.set(0, 0);    // to avoid warning
     if (paint.getFlags() & (SkPaint::kUnderlineText_Flag |
                             SkPaint::kStrikeThruText_Flag)) {
         width = paint.measureText(text, byteLength);
@@ skipping 283 matching lines @@
         iter.fDevice->drawAnnotation(iter, rect, key, value);
     }
     LOOPER_END
 }
 
 //////////////////////////////////////////////////////////////////////////////
 // These methods are NOT virtual, and therefore must call back into virtual
 // methods, rather than actually drawing themselves.
 //////////////////////////////////////////////////////////////////////////////
 
-void SkCanvas::drawARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b,
-                        SkXfermode::Mode mode) {
+void SkCanvas::drawARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b, SkBlendMode mode) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawARGB()");
     SkPaint paint;
 
     paint.setARGB(a, r, g, b);
-    if (SkXfermode::kSrcOver_Mode != mode) {
-        paint.setXfermodeMode(mode);
-    }
+    paint.setBlendMode(mode);
     this->drawPaint(paint);
 }
 
-void SkCanvas::drawColor(SkColor c, SkXfermode::Mode mode) {
+void SkCanvas::drawColor(SkColor c, SkBlendMode mode) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawColor()");
     SkPaint paint;
 
     paint.setColor(c);
-    if (SkXfermode::kSrcOver_Mode != mode) {
-        paint.setXfermodeMode(mode);
-    }
+    paint.setBlendMode(mode);
     this->drawPaint(paint);
 }
 
 void SkCanvas::drawPoint(SkScalar x, SkScalar y, const SkPaint& paint) {
     TRACE_EVENT0("disabled-by-default-skia", "SkCanvas::drawPoint(SkPaint)");
     SkPoint pt;
 
     pt.set(x, y);
     this->drawPoints(kPoints_PointMode, 1, &pt, paint);
 }
@@ skipping 429 matching lines @@
 const SkCanvas::ClipOp SkCanvas::kXOR_Op;
 const SkCanvas::ClipOp SkCanvas::kReverseDifference_Op;
 const SkCanvas::ClipOp SkCanvas::kReplace_Op;
 
 static_assert((int)SkRegion::kDifference_Op         == (int)kDifference_SkClipOp, "");
 static_assert((int)SkRegion::kIntersect_Op          == (int)kIntersect_SkClipOp, "");
 static_assert((int)SkRegion::kUnion_Op              == (int)kUnion_SkClipOp, "");
 static_assert((int)SkRegion::kXOR_Op                == (int)kXOR_SkClipOp, "");
 static_assert((int)SkRegion::kReverseDifference_Op  == (int)kReverseDifference_SkClipOp, "");
 static_assert((int)SkRegion::kReplace_Op            == (int)kReplace_SkClipOp, "");