One signature for creating unit tests that run on premade GrContexts

tests/RectangleTextureTest.cpp

Index: tests/RectangleTextureTest.cpp
diff --git a/tests/RectangleTextureTest.cpp b/tests/RectangleTextureTest.cpp
index 782a3b57b3e9ffec3a98c0ea0d5ff0ca2636ced1..a4a1cf7960becf6cc93a51f65a379ef22e2c9719 100644
--- a/tests/RectangleTextureTest.cpp
+++ b/tests/RectangleTextureTest.cpp
@@ -137,7 +137,9 @@ static void test_clear(skiatest::Reporter* reporter, GrContext* context,
     }
 }
 
-DEF_GPUTEST_FOR_RENDERING_CONTEXTS(RectangleTexture, reporter, context, glContext) {
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(RectangleTexture, reporter, ctxInfo) {
+    GrContext* context = ctxInfo.fGrContext;
+    sk_gpu_test::GLTestContext* glContext = ctxInfo.fGLContext;
     static const int kWidth = 13;
     static const int kHeight = 13;