Convert child FPs from refs to pending executions when parent converts

src/gpu/GrPrimitiveProcessor.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPrimitiveProcessor_DEFINED
 #define GrPrimitiveProcessor_DEFINED
 
@@ skipping 246 matching lines @@
     GrPrimitiveProcessor(bool isPathRendering)
         : fNumAttribs(0)
         , fVertexStride(0)
         , fIsPathRendering(isPathRendering) {}
 
     Attribute fAttribs[kMaxVertexAttribs];
     int fNumAttribs;
     size_t fVertexStride;
 
 private:
+    void notifyRefCntIsZero() const final {};
     virtual bool hasExplicitLocalCoords() const = 0;
 
     bool fIsPathRendering;
 
     typedef GrProcessor INHERITED;
 };
 
 #endif