Move instanced index buffer creation to flush time

include/gpu/GrTextureProvider.h

Index: include/gpu/GrTextureProvider.h
diff --git a/include/gpu/GrTextureProvider.h b/include/gpu/GrTextureProvider.h
index 3e29dabd47526404647ed0de339f0569567e2259..3f8c760f9b8c3b29343b8dba324143d1d04942da 100644
--- a/include/gpu/GrTextureProvider.h
+++ b/include/gpu/GrTextureProvider.h
@@ -154,6 +154,12 @@ protected:
         fGpu = NULL;
     }
 
+    GrResourceCache* cache() { return fCache; }
+    const GrResourceCache* cache() const { return fCache; }
+
+    GrGpu* gpu() { return fGpu; }
+    const GrGpu* gpu() const { return fGpu; }
+
 private:
     bool isAbandoned() const {
         SkASSERT(SkToBool(fGpu) == SkToBool(fCache));