Make GrDrawState and GrEffectStage use the pending io/exec ref mechanisms.

src/gpu/GrDrawTarget.h

Index: src/gpu/GrDrawTarget.h
diff --git a/src/gpu/GrDrawTarget.h b/src/gpu/GrDrawTarget.h
index 814d57f326792dadcd5793f6fd130a30bc4a8b85..8ffc68162799d6d45701f4661763058da2bd4a44 100644
--- a/src/gpu/GrDrawTarget.h
+++ b/src/gpu/GrDrawTarget.h
@@ -694,6 +694,10 @@ public:
     virtual DrawToken getCurrentDrawToken() { return DrawToken(this, 0); }
 
 protected:
+    // Extend access to GrRODrawState::convertToPEndeingExec to subclasses.
+    void convertDrawStateToPendingExec(GrRODrawState* ds) {
+        ds->convertToPendingExec();
+    }
 
     enum GeometrySrcType {
         kNone_GeometrySrcType,     //<! src has not been specified