Add method to GrProgramResource to record that pending a execution was completed.

include/gpu/GrProgramResource.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 GrProgramResource_DEFINED
 #define GrProgramResource_DEFINED
 
@@ skipping 41 matching lines @@
 private:
     /** Called by owning GrProgramElement when the program element is first scheduled for
         execution. */
     void markPendingIO() const;
 
     /** Called when the program element/draw state is no longer owned by GrDrawTarget-client code.
         This lets the cache know that the drawing code will no longer schedule additional reads or
         writes to the resource using the program element or draw state. */
     void removeRef() const;
 
-    friend class GrDrawState;
+    /** Called to indicate that the previous pending IO is complete. Useful when the owning object
+        still has refs, so it is not about to destroy this GrProgramResource, but its previously
+        pending executions have been complete.
+     */
+    void pendingIOComplete() const;
+
+    friend class GrRODrawState;
     friend class GrProgramElement;
 
     GrGpuResource*      fResource;
     mutable bool        fOwnRef;
     mutable bool        fPendingIO;
     IOType              fIOType;
 
     typedef SkNoncopyable INHERITED;
 };
 
 #endif