Miscellaneous GrSurfaceProxy-related cleanup

This is pulled out of: https://skia-review.googlesource.com/c/10284/ (Remove GrSurface-derived classes from ops)

Change-Id: I083c0beefe4899b3517d0b0569bb25096809f410
Reviewed-on: https://skia-review.googlesource.com/10483
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/tests/ClearTest.cpp b/tests/ClearTest.cpp
index d4b8587..843c4c3 100644
--- a/tests/ClearTest.cpp
+++ b/tests/ClearTest.cpp
@@ -17,12 +17,17 @@
 
 static bool check_rect(GrRenderTargetContext* rtc, const SkIRect& rect, uint32_t expectedValue,
                        uint32_t* actualValue, int* failX, int* failY) {
-    GrRenderTarget* rt = rtc->accessRenderTarget();
     int w = rect.width();
     int h = rect.height();
     std::unique_ptr<uint32_t[]> pixels(new uint32_t[w * h]);
     memset(pixels.get(), ~expectedValue, sizeof(uint32_t) * w * h);
-    rt->readPixels(rect.fLeft, rect.fTop, w, h, kRGBA_8888_GrPixelConfig, pixels.get());
+
+    SkImageInfo dstInfo = SkImageInfo::Make(w, h, kRGBA_8888_SkColorType, kPremul_SkAlphaType);
+
+    if (!rtc->readPixels(dstInfo, pixels.get(), 0, rect.fLeft, rect.fTop)) {
+        return false;
+    }
+
     for (int y = 0; y < h; ++y) {
         for (int x = 0; x < w; ++x) {
             uint32_t pixel = pixels.get()[y * w + x];