Add test configs for instanced rendering

src/gpu/GrDrawTarget.h

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDrawTarget_DEFINED
 #define GrDrawTarget_DEFINED
 
@@ skipping 121 matching lines @@
      * src bounds then  pixel values in the dst rect corresponding to area clipped
      * by the src rect are not overwritten. This method is not guaranteed to succeed
      * depending on the type of surface, configs, etc, and the backend-specific
      * limitations.
      */
     bool copySurface(GrSurface* dst,
                      GrSurface* src,
                      const SkIRect& srcRect,
                      const SkIPoint& dstPoint);
 
-    /**
-     * Gets the shape rendering object if it is supported on this platform.
-     */
-    gr_instanced::InstancedRendering* instancedRendering() const { return fInstancedRendering; }
+    gr_instanced::InstancedRendering* instancedRendering() const {
+        SkASSERT(fInstancedRendering);
+        return fInstancedRendering;
+    }
 
 private:
     friend class GrDrawingManager; // for resetFlag & TopoSortTraits
     friend class GrDrawContextPriv; // for clearStencilClip
 
     enum Flags {
         kClosed_Flag    = 0x01,   //!< This drawTarget can't accept any more batches
 
         kWasOutput_Flag = 0x02,   //!< Flag for topological sorting
         kTempMark_Flag  = 0x04,   //!< Flag for topological sorting
@@ skipping 75 matching lines @@
     bool                                            fDrawBatchBounds;
     int                                             fMaxBatchLookback;
     int                                             fMaxBatchLookahead;
 
     SkAutoTDelete<gr_instanced::InstancedRendering> fInstancedRendering;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif