Remove unused fRequiresVertexShader data member from 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 227 matching lines @@
     if (stage.getFragmentProcessor()->willReadFragmentPosition()) {
         *readsFragPosition = true;
     }
 }
 
 void GrOptDrawState::getStageStats() {
     // We will need a local coord attrib if there is one currently set on the optState and we are
     // actually generating some effect code
     fRequiresLocalCoordAttrib = this->hasLocalCoordAttribute() && this->numTotalStages() > 0;
 
-    // if 1 == fVACount then that VA must be position, otherwise it contains some attribute which
-    // will require a vertexShader
-    fRequiresVertexShader = fVACount > 1;
-
     fReadsDst = false;
     fReadsFragPosition = false;
 
     for (int s = 0; s < this->numColorStages(); ++s) {
         const GrFragmentStage& stage = this->getColorStage(s);
         get_stage_stats(stage, &fReadsDst, &fReadsFragPosition);
     }
     for (int s = 0; s < this->numCoverageStages(); ++s) {
         const GrFragmentStage& stage = this->getCoverageStage(s);
         get_stage_stats(stage, &fReadsDst, &fReadsFragPosition);
     }
     if (this->hasGeometryProcessor()) {
         const GrGeometryStage& stage = *this->getGeometryProcessor();
         fReadsFragPosition = fReadsFragPosition || stage.getProcessor()->willReadFragmentPosition();
-        SkASSERT(fRequiresVertexShader);
     }
 }
 
 bool GrOptDrawState::operator== (const GrOptDrawState& that) const {
     return this->isEqual(that);
 }