Begin instanced rendering for simple shapes

src/gpu/GrDrawContextPriv.h

Index: src/gpu/GrDrawContextPriv.h
diff --git a/src/gpu/GrDrawContextPriv.h b/src/gpu/GrDrawContextPriv.h
index 0641e9f2b5032ee786f4dfdc5cc7137b09edee51..3e3262485589f3826ae5e2ea5ffe8dd841ba6619 100644
--- a/src/gpu/GrDrawContextPriv.h
+++ b/src/gpu/GrDrawContextPriv.h
@@ -9,6 +9,7 @@
 #define GrDrawContextPriv_DEFINED
 
 #include "GrDrawContext.h"
+#include "GrDrawTarget.h"
 #include "GrPathRendering.h"
 
 class GrFixedClip;
@@ -20,6 +21,10 @@ struct GrUserStencilSettings;
     data members or virtual methods. */
 class GrDrawContextPriv {
 public:
+    gr_instanced::InstancedRendering* accessInstancedRendering() const {
+        return fDrawContext->getDrawTarget()->instancedRendering();
+    }
+
     void clearStencilClip(const SkIRect& rect, bool insideClip);
 
     void stencilRect(const GrFixedClip& clip,