Make skpaint->grpaint flow work for composing draws

src/core/SkShader.cpp

 /*
  * Copyright 2006 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 "SkAtomics.h"
 #include "SkBitmapProcShader.h"
 #include "SkColorShader.h"
@@ skipping 317 matching lines @@
     return kColor_GradientType;
 }
 
 #if SK_SUPPORT_GPU
 
 #include "SkGr.h"
 #include "effects/GrConstColorProcessor.h"
 const GrFragmentProcessor* SkColorShader::asFragmentProcessor(GrContext*, const SkMatrix&,
                                                               const SkMatrix*, SkFilterQuality,
                                                               GrProcessorDataManager*) const {
-    GrColor color = SkColor2GrColor(fColor);
+    GrColor color = SkColorToPremulGrColor(fColor);
     return GrConstColorProcessor::Create(color, GrConstColorProcessor::kModulateA_InputMode);
 }
 
 #endif
 
 #ifndef SK_IGNORE_TO_STRING
 void SkColorShader::toString(SkString* str) const {
     str->append("SkColorShader: (");
 
     str->append("Color: ");
@@ skipping 15 matching lines @@
 #include "SkEmptyShader.h"
 
 void SkEmptyShader::toString(SkString* str) const {
     str->append("SkEmptyShader: (");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif