Add check to see if we need to remove fixed funciton VA in OptDrawState

src/gpu/GrOptDrawState.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrOptDrawState.h"
 
 #include "GrDrawState.h"
@@ skipping 30 matching lines @@
     int firstCoverageStageIdx = 0;
     bool separateCoverageFromColor;
 
     uint8_t fixedFunctionVAToRemove = 0;
 
     this->computeEffectiveColorStages(drawState, &firstColorStageIdx, &fixedFunctionVAToRemove);
     this->computeEffectiveCoverageStages(drawState, &firstCoverageStageIdx);
     this->adjustFromBlendOpts(drawState, &firstColorStageIdx, &firstCoverageStageIdx,
                               &fixedFunctionVAToRemove);
     // Should not be setting any more FFVA to be removed at this point
-    this->removeFixedFunctionVertexAttribs(fixedFunctionVAToRemove);
+    if (0 != fixedFunctionVAToRemove) {
+        this->removeFixedFunctionVertexAttribs(fixedFunctionVAToRemove);
+    }
     this->getStageStats(drawState, firstColorStageIdx, firstCoverageStageIdx);
     this->setOutputStateInfo(drawState, caps, firstCoverageStageIdx, &separateCoverageFromColor);
 
     // Copy GeometryProcesssor from DS or ODS
     if (drawState.hasGeometryProcessor()) {
         fGeometryProcessor.initAndRef(drawState.fGeometryProcessor);
     } else {
         fGeometryProcessor.reset(NULL);
     }
 
@@ skipping 311 matching lines @@
         }
     }
 
     SkASSERT(0 == memcmp(this->fFixedFunctionVertexAttribIndices,
                          that.fFixedFunctionVertexAttribIndices,
                          sizeof(this->fFixedFunctionVertexAttribIndices)));
 
     return true;
 }