Use RGBA rather than N32 for GPU tests

This is to support a Mock backend that passes non-rendering context unit tests and has minimal config support.

Change-Id: I57c3ad2d347659d14382a8a7cf53424633bd86c6
Reviewed-on: https://skia-review.googlesource.com/21534
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/tests/ClipStackTest.cpp b/tests/ClipStackTest.cpp
index e1aa148..6f24908 100644
--- a/tests/ClipStackTest.cpp
+++ b/tests/ClipStackTest.cpp
@@ -1498,7 +1498,7 @@
 
     const int w = 10;
     const int h = 10;
-    SkImageInfo info = SkImageInfo::MakeN32Premul(w, h);
+    SkImageInfo info = SkImageInfo::Make(w, h, kRGBA_8888_SkColorType, kPremul_SkAlphaType);
     sk_sp<SkSurface> surf = SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, info);
     SkCanvas* canvas = surf->getCanvas();
     SkRegion rgn;