Fix to set correct output type when blending when we've read dst

src/gpu/GrOptDrawState.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrOptDrawState_DEFINED
 #define GrOptDrawState_DEFINED
 
@@ skipping 61 matching lines @@
     ///
     /// The input color to the first color-stage is either the constant color or interpolated
     /// per-vertex colors. The input to the first coverage stage is either a constant coverage
     /// (usually full-coverage) or interpolated per-vertex coverage.
     ////
 
     int numColorStages() const { return fNumColorStages; }
     int numCoverageStages() const { return fFragmentStages.count() - fNumColorStages; }
     int numFragmentStages() const { return fFragmentStages.count(); }
     int numTotalStages() const {
-         return this->numFragmentStages() + (this->hasGeometryProcessor() ? 1 : 0);
+        // the + 1 at the end is for the xferProcessor which will always be present
+        return this->numFragmentStages() + (this->hasGeometryProcessor() ? 1 : 0) + 1;
     }
 
     bool hasGeometryProcessor() const { return SkToBool(fGeometryProcessor.get()); }
     const GrGeometryProcessor* getGeometryProcessor() const { return fGeometryProcessor.get(); }
     const GrBatchTracker& getBatchTracker() const { return fBatchTracker; }
 
     const GrXferProcessor* getXferProcessor() const { return fXferProcessor.get(); }
 
     const GrPendingFragmentStage& getColorStage(int idx) const {
         SkASSERT(idx < this->numColorStages());
@@ skipping 148 matching lines @@
 
     // This function is equivalent to the offset into fFragmentStages where coverage stages begin.
     int                                 fNumColorStages;
 
     GrProgramDesc fDesc;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif