Clean up test drawContext usage

include/core/SkDevice.h

 /*
  * Copyright 2010 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkDevice_DEFINED
 #define SkDevice_DEFINED
 
@@ skipping 88 matching lines @@
      *  Try to get read-only-access to the pixels behind the device. If successful, this returns
      *  true and fills-out the pixmap parameter.
      *
      *  On failure, returns false and ignores the pixmap parameter.
      */
     bool peekPixels(SkPixmap*);
 
     /**
      * Return the device's associated gpu render target, or NULL.
      */
-    virtual GrRenderTarget* accessRenderTarget() { return NULL; }
+    virtual GrRenderTarget* accessRenderTarget() { return nullptr; }
 
+    /**
+     * Don't call this!
+     */
+    virtual GrDrawContext* accessDrawContext() { return nullptr; }
 
     /**
      *  Return the device's origin: its offset in device coordinates from
      *  the default origin in its canvas' matrix/clip
      */
     const SkIPoint& getOrigin() const { return fOrigin; }
 
     /**
      * onAttachToCanvas is invoked whenever a device is installed in a canvas
      * (i.e., setDevice, saveLayer (for the new device created by the save),
@@ skipping 280 matching lines @@
     SkSurfaceProps fSurfaceProps;
 
 #ifdef SK_DEBUG
     bool        fAttachedToCanvas;
 #endif
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif