Make createOptDrawState return NULL if we would end up not drawing

src/gpu/GrDrawState.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDrawState.h"
 
 #include "GrOptDrawState.h"
 #include "GrPaint.h"
 
 //////////////////////////////////////////////////////////////////////////////s
 
-GrOptDrawState* GrDrawState::createOptState(const GrDrawTargetCaps& caps) const {
-    if (NULL == fCachedOptState || caps.getUniqueID() != fCachedCapsID) {
-        GrBlendCoeff srcCoeff;
-        GrBlendCoeff dstCoeff;
-        GrOptDrawState::BlendOptFlags blendFlags =
-            (GrOptDrawState::BlendOptFlags) this->getBlendOpts(false, &srcCoeff, &dstCoeff);
-        fCachedOptState = SkNEW_ARGS(GrOptDrawState, (*this, blendFlags, srcCoeff, dstCoeff, caps));
-        fCachedCapsID = caps.getUniqueID();
-    } else {
-#ifdef SK_DEBUG
-        GrBlendCoeff srcCoeff;
-        GrBlendCoeff dstCoeff;
-        GrOptDrawState::BlendOptFlags blendFlags =
-            (GrOptDrawState::BlendOptFlags) this->getBlendOpts(false, &srcCoeff, &dstCoeff);
-        SkASSERT(GrOptDrawState(*this, blendFlags, srcCoeff, dstCoeff, caps) == *fCachedOptState);
-#endif
-    }
-    fCachedOptState->ref();
-    return fCachedOptState;
-}
-
-//////////////////////////////////////////////////////////////////////////////s
-
 bool GrDrawState::isEqual(const GrDrawState& that) const {
     bool usingVertexColors = this->hasColorVertexAttribute();
     if (!usingVertexColors && this->fColor != that.fColor) {
         return false;
     }
 
     if (this->getRenderTarget() != that.getRenderTarget() ||
         this->fColorStages.count() != that.fColorStages.count() ||
         this->fCoverageStages.count() != that.fCoverageStages.count() ||
         !this->fViewMatrix.cheapEqualTo(that.fViewMatrix) ||
@@ skipping 751 matching lines @@
         }
 
         // Since the shader will multiply coverage and color, the only way the final A==1 is if
         // coverage and color both have A==1.
         return (inoutColor.isOpaque() && inoutCoverage.isOpaque());
     }
 
     return inoutColor.isOpaque();
 }