Make createOptDrawState return NULL if we would end up not drawing

src/gpu/GrDrawState.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDrawState_DEFINED
 #define GrDrawState_DEFINED
 
@@ skipping 697 matching lines @@
 
     /** This function determines whether the GrDrawStates used for two draws can be combined into
         a single GrDrawState. This is used to avoid storing redundant GrDrawStates and to determine
         if draws can be batched. The return value indicates whether combining is possible and, if
         so, which of the two inputs should be used. */
     static CombinedState CombineIfPossible(const GrDrawState& a, const GrDrawState& b,
                                            const GrDrawTargetCaps& caps);
 
     GrDrawState& operator= (const GrDrawState& that);
 
-    /**
-     * Returns a snapshot of the current optimized state. If the current drawState has a valid
-     * cached optimiezed state it will simply return a pointer to it otherwise it will create a new
-     * GrOptDrawState. In all cases the GrOptDrawState is reffed and ownership is given to the
-     * caller.
-     */
-    GrOptDrawState* createOptState(const GrDrawTargetCaps&) const;
-
 private:
     /**
      * Converts refs on GrGpuResources owned directly or indirectly by this GrDrawState into
      * pending reads and writes. This should be called when a GrDrawState is recorded into
      * a GrDrawTarget for later execution. Subclasses of GrDrawState may add setters. However,
      * once this call has been made the GrDrawState is immutable. It is also no longer copyable.
      * In the future this conversion will automatically happen when converting a GrDrawState into
      * an optimized draw state.
      */
     void convertToPendingExec();
@@ skipping 86 matching lines @@
 
     uint32_t                            fHints;
 
     // This is simply a different representation of info in fVertexAttribs and thus does
     // not need to be compared in op==.
     int fFixedFunctionVertexAttribIndices[kGrFixedFunctionVertexAttribBindingCnt];
 
     mutable GrOptDrawState* fCachedOptState;
     mutable uint32_t fCachedCapsID;
 
+    friend class GrOptDrawState;
+
     typedef SkRefCnt INHERITED;
 };
 
-//GR_MAKE_BITFIELD_OPS(GrDrawState::BlendOptFlags);
+GR_MAKE_BITFIELD_OPS(GrDrawState::BlendOptFlags);
 
 #endif