Revert of Use dst copies in porter duffer XP to correctly render certain blends.

src/gpu/GrXferProcessor.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 "GrXferProcessor.h"
 #include "gl/GrGLCaps.h"
 
@@ skipping 20 matching lines @@
     this->onGetGLProcessorKey(caps, b);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrXferProcessor* GrXPFactory::createXferProcessor(const GrProcOptInfo& colorPOI,
                                                   const GrProcOptInfo& coveragePOI,
                                                   const GrDeviceCoordTexture* dstCopy,
                                                   const GrDrawTargetCaps& caps) const {
 #ifdef SK_DEBUG
-    if (this->willReadDstColor(caps, colorPOI, coveragePOI)) {
+    if (this->willReadDstColor(colorPOI, coveragePOI)) {
         if (!caps.dstReadInShaderSupport()) {
             SkASSERT(dstCopy && dstCopy->texture());
         } else {
             SkASSERT(!dstCopy || !dstCopy->texture()); 
         }
     } else {
         SkASSERT(!dstCopy || !dstCopy->texture()); 
+
     }
 #endif
-    return this->onCreateXferProcessor(caps, colorPOI, coveragePOI, dstCopy);
+    return this->onCreateXferProcessor(colorPOI, coveragePOI, dstCopy);
 }
 
 bool GrXPFactory::willNeedDstCopy(const GrDrawTargetCaps& caps, const GrProcOptInfo& colorPOI,
                                   const GrProcOptInfo& coveragePOI) const {
-    return (this->willReadDstColor(caps, colorPOI, coveragePOI) && !caps.dstReadInShaderSupport());
+    return (this->willReadDstColor(colorPOI, coveragePOI) && !caps.dstReadInShaderSupport());
 }