Make createOptDrawState return NULL if we would end up not drawing

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
 
-#include "GrDrawState.h"
+#include "GrColor.h"
+#include "GrGpu.h"
+#include "GrProcessorStage.h"
+#include "GrStencil.h"
+#include "GrTypesPriv.h"
+#include "SkMatrix.h"
+#include "SkRefCnt.h"
+
+class GrDrawState;
 
 /**
  * Class that holds an optimized version of a GrDrawState. It is meant to be an immutable class,
  * and contains all data needed to set the state for a gpu draw.
  */
 class GrOptDrawState : public SkRefCnt {
 public:
+    /**
+     * 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.
+     */
+    static GrOptDrawState* Create(const GrDrawState& drawState, const GrDrawTargetCaps& caps,
+                                  GrGpu::DrawType drawType);
+
     bool operator== (const GrOptDrawState& that) const;
 
     ///////////////////////////////////////////////////////////////////////////
     /// @name Vertex Attributes
     ////
 
     enum {
         kMaxVertexAttribCnt = kLast_GrVertexAttribBinding + 4,
     };
 
@@ skipping 407 matching lines @@
     bool            fRequiresLocalCoordAttrib;
 
     SkAutoSTArray<4, GrVertexAttrib> fOptVA;
 
     BlendOptFlags   fBlendOptFlags;
 
     // Fragment shader color outputs
     PrimaryOutputType  fPrimaryOutputType : 8;
     SecondaryOutputType  fSecondaryOutputType : 8;
 
-    friend GrOptDrawState* GrDrawState::createOptState(const GrDrawTargetCaps&) const;
     typedef SkRefCnt INHERITED;
 };
 
 GR_MAKE_BITFIELD_OPS(GrOptDrawState::BlendOptFlags);
 
 #endif