Make a single GrSingleOwner in GrContext

include/gpu/GrDrawContext.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDrawContext_DEFINED
 #define GrDrawContext_DEFINED
 
@@ skipping 265 matching lines @@
     int numColorSamples() const { return fRenderTarget->numColorSamples(); }
 
     GrRenderTarget* accessRenderTarget() { return fRenderTarget; }
 
 private:
     friend class GrAtlasTextBlob; // for access to drawBatch
     friend class GrDrawingManager; // for ctor
 
     SkDEBUGCODE(void validate() const;)
 
-    GrDrawContext(GrDrawingManager*, GrRenderTarget*, const SkSurfaceProps* surfaceProps);
+    GrDrawContext(GrDrawingManager*, GrRenderTarget*, const SkSurfaceProps* surfaceProps,
+                  GrSingleOwner*);
 
     void internalDrawPath(GrPipelineBuilder*,
                           const SkMatrix& viewMatrix,
                           GrColor,
                           bool useAA,
                           const SkPath&,
                           const GrStrokeInfo&);
 
     // This entry point allows the GrTextContext-derived classes to add their batches to
     // the drawTarget.
     void drawBatch(GrPipelineBuilder* pipelineBuilder, GrDrawBatch* batch);
 
     GrDrawTarget* getDrawTarget();
 
     GrDrawingManager* fDrawingManager;
     GrRenderTarget*   fRenderTarget;
 
     // In MDB-mode the drawTarget can be closed by some other drawContext that has picked
     // it up. For this reason, the drawTarget should only ever be accessed via 'getDrawTarget'.
     GrDrawTarget*     fDrawTarget;
     GrTextContext*    fTextContext; // lazily gotten from GrContext::DrawingManager
 
     SkSurfaceProps    fSurfaceProps;
 
     // In debug builds we guard against improper thread handling
-    SkDEBUGCODE(mutable GrSingleOwner fSingleOwner;)
+    mutable GrSingleOwner* fSingleOwner;
 };
 
 #endif