One signature for creating unit tests that run on premade GrContexts

tests/PremulAlphaRoundTripTest.cpp

Index: tests/PremulAlphaRoundTripTest.cpp
diff --git a/tests/PremulAlphaRoundTripTest.cpp b/tests/PremulAlphaRoundTripTest.cpp
index 5cc7a493c62e6764e208e4373825fa00171a5dc7..26badb66c4375e553cd9fcb6924304b9f5558201 100644
--- a/tests/PremulAlphaRoundTripTest.cpp
+++ b/tests/PremulAlphaRoundTripTest.cpp
@@ -105,11 +105,11 @@ DEF_TEST(PremulAlphaRoundTrip, reporter) {
     test_premul_alpha_roundtrip(reporter, device);
 }
 #if SK_SUPPORT_GPU
-DEF_GPUTEST_FOR_RENDERING_CONTEXTS(PremulAlphaRoundTrip_Gpu, reporter, context) {
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(PremulAlphaRoundTrip_Gpu, reporter, ctxInfo) {
     const SkImageInfo info = SkImageInfo::MakeN32Premul(256, 256);
     SkSurfaceProps props(SkSurfaceProps::kLegacyFontHost_InitType);
     SkAutoTUnref<SkBaseDevice> device(
-        SkGpuDevice::Create(context, SkBudgeted::kNo, info, 0, &props,
+        SkGpuDevice::Create(ctxInfo.fGrContext, SkBudgeted::kNo, info, 0, &props,
                             SkGpuDevice::kUninit_InitContents));
     test_premul_alpha_roundtrip(reporter, device);
 }