Move instanced index buffer creation to flush time

Review URL: https://codereview.chromium.org/1116943004
diff --git a/src/gpu/GrAddPathRenderers_default.cpp b/src/gpu/GrAddPathRenderers_default.cpp
index 06e98a9..0f675ac 100644
--- a/src/gpu/GrAddPathRenderers_default.cpp
+++ b/src/gpu/GrAddPathRenderers_default.cpp
@@ -39,7 +39,7 @@
     if (GrPathRenderer* pr = GrStencilAndCoverPathRenderer::Create(ctx)) {
         chain->addPathRenderer(pr)->unref();
     }
-    if (GrPathRenderer* pr = GrAAHairLinePathRenderer::Create(ctx)) {
+    if (GrPathRenderer* pr = GrAAHairLinePathRenderer::Create()) {
         chain->addPathRenderer(pr)->unref();
     }
     chain->addPathRenderer(SkNEW(GrAAConvexPathRenderer))->unref();